Start with the simplest fixes first

Most computer problems go away after a restart. Before you do anything else, save your work, close your programs, and shut down your computer completely — not sleep mode, but a full shutdown. Wait 30 seconds, then turn it back on. This clears temporary files and resets connections that may have gotten stuck.

If the problem persists, the next step depends on what is actually broken. A computer that won't turn on needs different troubleshooting than one that turns on but runs slowly, or one that crashes when you open a specific program. Knowing which category your problem falls into will save you time and point you toward the real cause.

Key Takeaways

  • A full restart solves roughly half of common computer problems and should always be your first step.
  • Slow performance usually comes from too many programs running at startup, a full hard drive, or malware — each has a different fix.
  • If your computer won't turn on, check the power cable and outlet before assuming the hardware has failed.
  • Windows and Mac both have built-in repair tools — Windows has Startup Repair, and Mac has Disk Utility — that can fix file system errors without outside software.
  • If a single program crashes repeatedly, uninstalling and reinstalling it often works better than trying to repair the installation.

What to do if your computer runs slowly

Slow performance usually has one of three causes: too many programs launching at startup, a hard drive that is nearly full, or malware running in the background. Start by checking how full your drive is. On Windows, right-click the C: drive in File Explorer, select Properties, and look at the pie chart. If the blue section (used space) takes up more than 80 percent of the circle, your computer is struggling. Delete old files, empty your Downloads folder, and uninstall programs you no longer use.

Next, check what programs are set to launch when you start your computer. On Windows 11, press Ctrl+Shift+Esc to open Task Manager, click the Startup tab, and look at the Impact column. Anything marked High or Medium that you do not need running all the time can be disabled — right-click it and select Disable. On a Mac, go to System Settings, General, Login Items, and remove programs from the Allow in the Login Window list.

If your drive is not full and startup programs are not the problem, run a malware scan. Windows Defender (built into Windows) and Malwarebytes (free version available) both work well. Open Windows Defender by typing "Windows Security" into the search box, click Virus & Threat Protection, then Scan Options, and select Full Scan. Let it run completely — this can take an hour or more.

How to fix a computer that won't turn on

Before you assume the hardware is broken, check the basics. Make sure the power cable is plugged into both the computer and the wall outlet, and that the outlet itself works — plug a lamp into it to test. If the outlet is controlled by a switch, make sure the switch is on. Try a different power cable if you have one available, because cables fail more often than power supplies do.

If the computer still will not turn on, hold the power button for 10 seconds to force a complete shutdown, then wait 30 seconds and try again. Sometimes the computer gets stuck in a state where it appears off but is not fully shut down. If you hear the fan running or see lights on the case, the computer is getting power — the problem is likely the display, not the power supply. Try unplugging the monitor, waiting 10 seconds, and plugging it back in.

If nothing turns on — no lights, no fan noise, no response to the power button — and you have confirmed the outlet works, the power supply or motherboard may have failed. This is a repair that usually requires professional help or replacement of the computer.

Fixing crashes and error messages

When a program crashes repeatedly, the fastest fix is usually to uninstall and reinstall it. Go to Settings on Windows (or System Settings on Mac), find Apps or Applications, locate the program, and select Uninstall. Restart your computer, then read a fresh copy from the program's official website and install it again. This replaces corrupted files that a straightforward repair cannot fix.

If your entire computer crashes and shows a blue screen with white text (Windows) or a gray screen with a spinning wheel (Mac), write down any error code or message you see. Search for that exact error code online — most have documented solutions. Common Windows errors like "DRIVER_IRQL_NOT_LESS_OR_EQUAL" usually point to a specific driver that needs updating.

To update drivers on Windows, right-click the Start button, select Device Manager, find the device with a yellow warning triangle, right-click it, and select Update Driver. Choose "Search automatically for updated driver software." On a Mac, go to System Settings, General, Software Update, and install any available updates.

Using Windows Startup Repair and Mac Disk Utility

Both Windows and Mac include built-in tools that can fix file system errors without additional software. On Windows, Startup Repair runs automatically if Windows detects a problem during boot. If it does not start automatically, you can force it by restarting your computer and pressing F8 repeatedly as it boots (on older Windows versions) or by using a Windows installation USB and selecting Repair Your Computer.

On a Mac, restart your computer and hold Command+S to boot into Single User Mode, then type fsck -fy and press Enter. This checks and repairs the file system. If errors are found, run the command again until it reports "The volume appears to be OK." Alternatively, restart while holding Command+R to enter Recovery Mode, open Disk Utility from the Utilities menu, select your drive, and click First Aid.

These tools fix file corruption that can cause crashes or prevent your computer from starting. They do not recover deleted files or remove malware — they repair the structure of your hard drive itself.

When to back up your data before troubleshooting

If your computer still turns on and you can access your files, back them up before trying major repairs. Copy important documents, photos, and files to an external drive or cloud storage like Google Drive, OneDrive, or iCloud. This takes 15 minutes and protects you if a repair attempt goes wrong or if your hard drive fails during troubleshooting.

If your computer will not turn on at all, you cannot back up your data yourself — that requires professional data recovery, which is expensive. If the files are critical, contact a local computer repair shop before attempting any fixes.

When to call a professional

Call a professional if your computer makes unusual noises (clicking, grinding, or beeping), if it overheats and shuts down repeatedly even after cleaning the vents, if it will not turn on and you have confirmed the power cable works, or if a crash is tied to a specific hardware component (like a graphics card or RAM) that you are not comfortable replacing yourself.

You should also seek help if you have run malware scans and the computer is still slow, if you see repeated error messages about a specific file or driver that you cannot locate, or if you have tried uninstalling and reinstalling a program and it still crashes. A repair technician can run diagnostic software that identifies hardware failures and can safely replace components.

Frequently Asked Questions

Is it safe to force restart my computer by holding the power button?

Yes, holding the power button for 10 seconds forces a shutdown and is safe to do occasionally. It bypasses the normal shutdown process, so avoid doing it repeatedly, but it is the correct way to shut down a computer that is completely frozen and not responding to keyboard or mouse input.

What does it mean if my computer is running hot?

Heat usually means dust is blocking airflow inside the case or the fan is not spinning properly. Shut down your computer, unplug it, and use compressed air to blow dust out of the vents and fan openings. If the computer is still hot after cleaning, the fan may be failing and needs replacement.

Can I fix a virus myself or do I need to take it to a shop?

You can run malware scans yourself using Windows Defender or Malwarebytes, and most viruses are caught and removed by these tools. If scans find nothing but your computer is still slow or behaving strangely, or if you see repeated pop-ups, a technician can do a deeper scan and may recommend a full reinstall of Windows.

What should I do if I see a message saying my hard drive is failing?

Back up your data when ready to an external drive or cloud storage, then take the computer to a repair shop. A failing hard drive can stop working without warning, and once it fails completely, data recovery is expensive. Replacing a hard drive before it fails is much cheaper than recovering data after it does.

How often should I restart my computer?

Restarting once a week is a good habit for most users. It clears temporary files, resets network connections, and installs updates that Windows or Mac may have downloaded. If your computer is running slowly or behaving oddly, restart it before trying anything else.