Complete Guide to Troubleshooting a PC: Steps, Tools, & Tips

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Learn to diagnose and fix any PC issue
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Whether you're having a computer problem right now or want to learn how to troubleshoot for career advancement, you've come to the right place. Various things could go wrong with a computer, but you can usually track down and fix the problem on your own once you learn the troubleshooting process and all the helpful tools available on your PC or Mac. We spoke with computer and tech specialist Luigi Oppido to prepare this helpful guide to troubleshooting a computer, covering software and internet troubleshooting, malware and virus removal, and even hardware diagnostics. We'll also answer some frequently asked questions about troubleshooting.

Troubleshooting a PC

Tech specialist Luigi Oppido says the first thing to do if a computer isn't working is to make sure it's plugged in and receiving power. Reboot your computer and install updates. Use Task Manager, Activity Monitor, and troubleshooters to diagnose performance issues.

Section 1 of 7:

Basic Troubleshooting Steps

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  1. It may seem like a simple suggestion, but rebooting your computer will fix many of the problems you may be having. If the computer is not responding, press and hold the Power button until the computer powers down.
    • Allow your computer to sit for about thirty seconds after being turned off before you turn it back on again.
  2. The best way to troubleshoot a problem is to figure out how to reproduce it. What were you doing when the problem occurred? If you do that thing again, does the problem keep happening? Think back to when the computer started having issues. Was a certain program installed, or a change made to the hardware? Was something suspicious downloaded or installed with a program you got? Was there a power outage and now things aren't working correctly? Narrowing down the possible cause of the problem will make it much easier to determine how to proceed.
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  3. Loose or bad cables can cause all types of issues, from your mouse and keyboard not working to your computer not starting at all. Before you get too deep into troubleshooting, make sure all cables connected to your computer, monitor, and peripherals are securely in place.
    • If the computer won't turn on, the issue may be related to a cord, a surge protector, or even the power outlet it's plugged into. Oppido recommends unplugging it from power and plugging a different device into the same outlet to rule out power issues in your home or office. "If it's a laptop," he says, "double-check to make sure the AC adapter is functional and properly connected. [2]
    • Try plugging your computer directly into the wall instead of a surge protector to rule out a bad surge protector.
  4. Updating your programs, operating system, and hardware drivers can solve numerous problems. Whether your computer keeps freezing and crashing or running slow, an update may be all you need. The update process varies depending on what you're trying to update.
    • Windows checks for and installs updates automatically, generally including hardware drivers. You can also check for updates manually .
    • macOS will prompt you and a new operating system update is available, but you can check for updates at any time.
    • Most drivers update with the operating system, but some may require manual updates .
    • On Windows, open the Microsoft Store app to see if any software updates are available. On a Mac, you can check the App Store. You can also check for updates for individual programs from within each program.
  5. 5
    Use your computer's built-in performance monitoring tools. To force-close apps, determine which programs use the most resources, and monitor available CPU power and RAM, you will need to become familiar with tools like Task Manager and Performance Monitor on Windows, and Activity Monitor on a Mac.
    • To open Task Manager on Windows, press Ctrl + ⇧ Shift + Esc .
    • To open Performance Monitor, type performance into the Windows search bar, then click Performance Monitor in the search results.
    • To open Activity Monitor on macOS, open the Applications folder in Finder, open the Utilities folder, and then double-click Activity Monitor .
  6. There are countless issues your computer could be experiencing. Problems can occur with your programs, operating system, hardware, or network setup. While covering every problem in this article is impossible, there's a good chance someone else has had the same problem you're facing. Searching Google for possible solutions is often the fastest way to get your computer working again.
    • Be specific with your search. Include the program's name and your operating system. Search for the exact error message along with any error codes. Focus on keywords that describe your problem. Try to narrow it down to your situation as much as possible.
    • Focus on tech forums when browsing through the search results. You will often find the most in-depth guides and useful suggestions from these sites.
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Section 2 of 7:

Speeding Up a Slow Computer

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  1. The more programs you run on your computer simultaneously, the slower it will run. Your operating system will often load several programs in the background when it starts.
    • In Windows, many programs running in the background will have icons in your System Tray. Right-click on these icons to close the programs.
    • Make sure you save any work before closing a program.
    • Avoid downloading programs that claim to speed up your computer. These are nearly all scams or vehicles for adware. You can boost your computer's speed on your own without the help of these programs.
  2. The only way to close these programs may be by forcing them to close. There are several ways that you can do this:
    • Windows - Press Alt + F4 to force the active program to close. If Alt + F4 isn't working, press Ctrl + ⇧ Shift + Esc to open a list of all the running programs. Select the program you want to force to close and click End task .
    • Mac - Press ⌘ Cmd + ⌥ Opt + Esc to open a list of your open programs. Select the program you want to force-close and click Force Quit . You can also hold ⌘ Cmd + ⌥ Opt + ⇧ Shift + Esc for three seconds to force-close the active program.
  3. Many programs will set themselves to start immediately when your operating system boots. When you try to launch too many programs, the startup process can take a long time. Removing programs you don't use from your startup list will help speed up the time your computer takes to boot. It will also reduce the general load as you use the computer.
    • On Windows, press Ctrl + ⇧ Shift + Esc to open Task Manager and click the Startup apps tab to see which programs start automatically. To prevent an app from starting automatically at boot time, right-click it and select Disable .
    • On a Mac, remove startup items at Apple menu > System Settings > General > Login Items & Extensions . [3]
  4. For your operating system to run efficiently, you'll want at least 15-20% of your total storage space free. This allows the operating system to write temporary files that will allow it to run more smoothly.
    • One of the quickest ways to free up space is to delete unnecessary files , such as those in your Downloads folder, Recycle Bin, or Trash. This could include old installers for programs, downloaded music and videos, and large documents.
    • Deleting programs you no longer use can also free up a lot of space. This is especially true with some video games, which can take 30 GB or more of your hard disk space.
    • The Disk Cleanup tool in Windows will scan for files that you no longer use. It can free up a large amount of space.
  5. If the components in your computer are getting too hot, they may be slowing down to prevent damage. This can slow your computer down. Use a free tool like SpeedFan to ensure your computer hardware temperatures are within an acceptable range.
  6. A computer that was running fine and then suddenly became slow may be infected with a virus or other type of malware. Regular antivirus scans will help protect your system from viruses. Viruses affect your computer's performance and put your personal data at risk.
    EXPERT TIP

    Luigi Oppido

    Computer & Tech Specialist
    Luigi Oppido is the Owner and Operator of Pleasure Point Computers in Santa Cruz, California. Luigi has over 25 years of experience in general computer repair, data recovery, virus removal, and upgrades. He is also the host of the Computer Man Show! broadcasted on KSQD covering central California for over two years.
    Luigi Oppido
    Computer & Tech Specialist

    Scan your computer for malware once a week. If you notice any characteristics of change, like slowness, or if the computer isn't acting the way it did yesterday, it never hurts to scan.

  7. Disabling these effects is highly recommended for older PCs and can result in a big performance boost.
    • Type advanced system settings into the Windows search bar and click the Control Panel result.
    • Click the Settings… button under "Performance."
    • Select Adjust for best performance to quickly disable all unnecessary visual features and animations, or select Custom and disable things manually.
  8. Oftentimes, the easiest way to speed up your computer is to wipe it clean and start from scratch. Reinstalling Windows or reinstalling macOS usually won't take more than an hour or so. The process will erase your entire hard drive, often making the computer operate as if it were brand new.
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Section 3 of 7:

Troubleshooting Network Problems

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  1. Like with many computer problems, restarting your computer may help fix your networking issues. Make sure to save any open files before restarting.
  2. There's a good chance that a quick reset of your hardware will fix the problem. This trick, known as a "power cycle," is always the first troubleshooting step a tech support agent will ask you to do when helping you fix internet connection problems. This is because it works!
    • Find your modem and router (if you have one) and remove the power cables from the back of each.
    • Wait at least thirty seconds, then plug the power cable back into the modem.
    • Wait until the modem has finished powering on and connecting. This could take a minute or more.
    • Plug the power cable back in for the router once the modem has connected.
    • Wait several minutes, then try to connect to the internet again.
  3. There may be a problem with your DNS cache if certain sites aren't loading. The DNS cache stores the hostnames of the websites you visit. If it gets corrupted or out-of-date, you may be unable to connect to certain sites. You can easily flush the DNS cache on Windows, macOS, and Linux.
  4. If you live in an apartment complex or dorm, dozens of wireless networks may be in range. This can cause a lot of interference and dropped connections. Changing the channel for your wireless network may help fix interference.
  5. If you can't connect to the internet, your ISP may be experiencing an outage, or there could be a problem with your account. Contact your ISP's technical support if you've tried resetting everything yourself.
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Section 4 of 7:

Removing Viruses and Malware

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  1. You may have accidentally installed adware alongside another program downloaded from the internet. The main symptoms are a lot of pop-ups when browsing the internet or redirected searches. These steps will help with most adware, though you may need to search for solutions for your specific infection.
  2. Windows comes with a free antivirus and antimalware scanning tool. If you are using a different operating system, you can download a free antimalware tool like Malwarebytes .
    • Oppido recommends keeping a live-time antimalware scanner running to protect your computer. "Say you’re browsing the internet without protection and notice something wrong. A live-time scanner protects your computer like a gatekeeper," he explains. "It watches every single file that comes in and out." [5]
    • Windows comes with a live-time scanning tool (Microsoft Defender). However, Oppido explains, "If you're using a Mac, there's nothing good out there that you can get for free." In this case, you could download a real-time scanning program like Malwarebytes, which Oppido notes is the "industry standard for malware removal." [6]
  3. If you're using Google Chrome or Microsoft Edge, you can reset the browser to its original settings to quickly reverse any weird changes made to your settings by adware or malware.
    • Chrome
    • Click the menu at the top-right corner and select Settings .
    • Select Reset settings and then click Restore settings to their original defaults.
    • Click Reset settings . [7]
    • Edge
      • Click the menu at the top-right and select Settings .
      • Click Reset settings in the left panel.
      • Click Restore settings to their default values .
      • Click Reset to confirm.
    EXPERT TIP

    Luigi Oppido

    Computer & Tech Specialist
    Luigi Oppido is the Owner and Operator of Pleasure Point Computers in Santa Cruz, California. Luigi has over 25 years of experience in general computer repair, data recovery, virus removal, and upgrades. He is also the host of the Computer Man Show! broadcasted on KSQD covering central California for over two years.
    Luigi Oppido
    Computer & Tech Specialist

    Only install browser extensions you trust. A lot of the attacks we’ve been seeing have come through vulnerabilities in browser extensions. Even if you have protection on your computer, bad extensions can supersede your antivirus and change your browser.

  4. The steps above are general adware removal steps, but many infections require extra steps, such as resetting the hosts file or fixing browser shortcuts.
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Section 5 of 7:

Troubleshooting Hardware

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  1. Errors on your hard drive can cause your computer to slow down, corrupt files, or prevent you from loading programs or the operating system. Windows and Mac have tools that can find and correct some errors. If your hard drive is failing, you'll need to replace it.
    • On Windows, you can check for and repair disk errors from File Explorer:
      • Press Windows key + E to open File Explorer.
      • Under "This PC" in the left panel, right-click the drive you want to check and select Properties .
      • Click the Tools tab.
      • Click Check under "Error checking" and click Yes to confirm.
      • Check the boxes next to "Automatically Fix File System Errors" and "Scan For And Attempt Recovery Of Bad Sectors".
      • Click Start . [8]
    • On a Mac, you can use Disk Utility:
      • Shut down your Mac.
      • Press and hold the Power button until the system volume and Options button appear.
      • Click the Options button and then Continue .
      • Log in with your administrator account.
      • Open Disk Utility and go to View > Show all devices .
      • Select the volume you want to check or repair and click the stethoscope icon.
      • Follow the on-screen instructions to check for errors and repair them.
      • Repeat for all volumes. [9]
  2. If your computer isn't booting properly or crashes a lot, there could be a problem with one or more of your memory modules. If your RAM has gone bad, you will need to replace it. Replacing RAM is easy if you have a desktop computer or are using certain PC laptops. Some laptops, however, make it difficult to replace bad RAM.
    • On Windows, you can test RAM using Windows Memory Diagnostic Tool:
      • Type windows memory into the search bar and select Windows Memory Diagnostic .
      • Save and close all other open programs.
      • Select Restart now and check for problems (recommended) and wait for your computer to reboot and test the RAM. [10]
    • On a Mac, you can run Apple Diagnostics to check for all hardware problems, including bad RAM:
      • Shut down your Mac.
      • On Apple Silicon processors, press and hold the power button until you see the Options screen, then release. Press and hold ⌘ Command + D to run diagnostic tests. [11]
      • If you have an Intel processor, turn on your Mac, then press and hold the D key on your keyboard until you see a progress bar or are asked to select a language. Then, follow the on-screen instructions to run diagnostic tests.
  3. The power supply is the unit that takes in power from the wall and then sends it to each of your computer's components. If the power supply is failing, your computer may crash or refuse to start at all. If your hardware draws more power than your power supply can provide, your computer may crash whenever it is under a heavy load.
  4. If you're having problems with the image, it's usually either the monitor or graphics card. Plug a new monitor into the computer if possible. If the image works on the new monitor, then your old monitor is faulty. If the image doesn't work on the new monitor, there is likely an issue with your graphics card, and you will need to replace it.
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Section 6 of 7:

Troubleshooting a Noisy Computer

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  1. The main cause of a noisy computer is usually dust buildup inside. Cleaning out your computer will help keep the heat and noise to a minimum. Clean the inside of the computer every six months. Clean more frequently if you have pets or smoke.
  2. The fans inside your computer keep it cool, but are also the largest source of noise. Replacing your fans with larger, more efficient ones can keep it quieter and cooler.
  3. One of the loudest fans in the computer is usually the CPU fan. This is because the CPU is typically the hottest component, so the CPU fan is often running at maximum speed. Replacing your CPU cooler with a more efficient one can reduce the noise coming from your computer.
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Section 7 of 7:

FAQ

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  1. 1
    What are the 5 basic troubleshooting steps for a computer? If you are just getting started in IT (or perhaps studying for the CompTIA exam), it will be helpful to know the first five troubleshooting steps for any computer issue: [13]
    • Identify the problem
    • Consider the most likely cause
    • Test your theory
    • Establish a plan
    • Implement the fix
  2. 2
    How do you troubleshoot a computer if it is not responding? If the computer is completely frozen and you are unable to force-close programs, your first job as a troubleshooter is to make it responsive again.
    • First, turn the computer off. You can usually do this by pressing and holding the power button until the screen goes dark.
    • Wait a few moments, then press the power button once to turn it back on.
    • Depending on your computer, you may be prompted to check for errors once you turn the computer back on. If so, follow the on-screen prompts–this will often help you avoid data loss.
    • Once the computer comes back up, check the logs.
      • On a PC, you can check the Event Viewer to see what led to the freeze.
      • On a Mac, use the Console .
    • If you can't get back into the operating system, start the computer in Safe Mode.
    • From there, you can check the logs, uninstall problematic apps, and install updates.
  3. 3
    How do you learn how to troubleshoot computers? The best way to learn how to troubleshoot is to gain experience. Try to fix problems yourself before asking for help. If you get an error, search for it on the web and learn how to fix it yourself. Don't ask; just experiment and be willing to break things. When your friends and family have computer problems, offer to fix them.
    • If you're considering pursuing a career in IT, understand that while a troubleshooting methodology can be taught in a classroom, the best way to learn to troubleshoot is to have a big computer problem in front of you that you must fix. Troubleshooting skill comes with experience, and the best IT pros are often self-taught.
  4. 4
    What is troubleshooting? Troubleshooting is the step-by-step process of identifying a problem, determining the source or cause of the problem, and implementing a solution.
  5. 5
    How do I put a PC into troubleshoot mode? If you want to troubleshoot a specific function of your PC, you can use a Windows Troubleshooter. To do this, type troubleshoot into the Windows search bar, click Troubleshoot settings in the search results, then click Other troubleshooters . Click the troubleshooter you want to run.
    • If you want to troubleshoot a problem in Safe Mode, go to Start > Settings .
    • On Windows 10, go to Update & Security > Recovery. On Windows 11, go to System > Recovery.
    • Click Restart Now next to "Advanced startup."
    • When the PC reboots, go to Troubleshoot > Advanced Options > Startup Settings > Restart.
    • When the computer reboots again, press 5 to start Safe Mode with Networking (if you need internet access), or 4 to start Safe Mode without networking. [14]
  6. 6
    How do I put my PC in repair mode? To run a startup repair on Windows:
    • Start your PC and wait for the Windows or manufacturer logo.
    • As soon as the logo appears, press and hold the power button until the computer turns off.
    • Turn your computer on again.
    • Again, when you see the logo, press and hold the power button until the computer turns off.
    • Turn your PC back on. You will see the "Automatic Repair" screen.
    • Click Advanced options.
    • Click Restart to run a startup repair.
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Expert Q&A

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  • Question
    Why do I keep getting viruses if I have antivirus software installed?
    Luigi Oppido
    Computer & Tech Specialist
    Luigi Oppido is the Owner and Operator of Pleasure Point Computers in Santa Cruz, California. Luigi has over 25 years of experience in general computer repair, data recovery, virus removal, and upgrades. He is also the host of the Computer Man Show! broadcasted on KSQD covering central California for over two years.
    Luigi Oppido
    Computer & Tech Specialist
    Expert Answer
    Check your browser extensions and make sure they're actually safe. A lot of viruses actually sneak in through poorly-designed or malicious extensions.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
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    Not Helpful 2 Helpful 0
  • Question
    Why isn't my computer turning on?
    Luigi Oppido
    Computer & Tech Specialist
    Luigi Oppido is the Owner and Operator of Pleasure Point Computers in Santa Cruz, California. Luigi has over 25 years of experience in general computer repair, data recovery, virus removal, and upgrades. He is also the host of the Computer Man Show! broadcasted on KSQD covering central California for over two years.
    Luigi Oppido
    Computer & Tech Specialist
    Expert Answer
    Start by making sure it's actually plugged in. If it is, try another outlet just to make sure. From there, you may need to test the power supply. If it's a laptop, make sure that your charger is actually working. Beyond that, it may be time to take it in for repairs. If you're handy yourself, you could look at the RAM
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 0 Helpful 1
  • Question
    Should I replace my laptop battery if I think it's dying quickly?
    Luigi Oppido
    Computer & Tech Specialist
    Luigi Oppido is the Owner and Operator of Pleasure Point Computers in Santa Cruz, California. Luigi has over 25 years of experience in general computer repair, data recovery, virus removal, and upgrades. He is also the host of the Computer Man Show! broadcasted on KSQD covering central California for over two years.
    Luigi Oppido
    Computer & Tech Specialist
    Expert Answer
    You can, but it may not be worth it to you. You really only need the battery if you take your laptop off of your desk or travel with it.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
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      References

      1. ↑ https://support.microsoft.com/en-us/windows/system-restore-a5ae3ed9-07c4-fd56-45ee-096777ecd14e
      2. ↑ Luigi Oppido. Computer & Tech Specialist. Expert Interview. 31 July 2019.
      3. ↑ https://support.apple.com/guide/mac-help/remove-login-items-resolve-startup-problems-mh21210/mac
      4. ↑ Luigi Oppido. Computer & Tech Specialist. Expert Interview. 31 July 2019.
      5. ↑ Luigi Oppido. Computer & Tech Specialist. Expert Interview. 31 July 2019.
      6. ↑ Luigi Oppido. Computer & Tech Specialist. Expert Interview. 31 July 2019.
      7. ↑ https://support.google.com/chrome/answer/3296214?hl=en
      8. ↑ https://www.seagate.com/support/kb/what-do-i-do-if-my-drive-reports-bad-sectors-196351en/
      9. ↑ https://support.apple.com/guide/mac-help/macos-recovery-a-mac-apple-silicon-mchl82829c17/mac
      1. ↑ https://www.microsoft.com/en-us/surface/do-more-with-surface/how-to-use-windows-memory-diagnostic
      2. ↑ https://support.apple.com/en-us/102550
      3. ↑ Luigi Oppido. Computer & Tech Specialist. Expert Interview. 31 July 2019.
      4. ↑ https://www.comptia.org/blog/troubleshooting-methodology
      5. ↑ https://www.dell.com/support/kbdoc/en-us/000124344/how-to-boot-to-safe-mode-in-windows-10

      About This Article

      Article Summary X

      1. Restart the computer.
      2. Search for the exact error message online.
      3. Check all of the cables.
      4. Install available updates.
      5. Close unused programs.
      6. Free up hard drive space.
      7. Run virus and malware scans.
      8. Reinstall the operating system.

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