Start with the basics: restart, check connections, and look for error messages

Most computer problems go away after a restart. Power down completely, wait 30 seconds, and turn it back on. This clears temporary files and resets connections that may have frozen. If the problem returns after restart, the next step is to check the physical connections: make sure cables are plugged in firmly at both ends, that your monitor is connected to power and to the computer (not just powered on), and that any external devices like printers or external drives are seated properly in their ports.

Before you dig deeper, write down any error messages you see exactly as they appear on screen. Take a photo if the message disappears. Error messages tell you what went wrong and where—they are the computer's way of describing the problem in its own language. A message like "No internet connection" points you toward network troubleshooting, while "Disk full" means you need to delete files. The exact wording matters when you search for solutions later.

Key Takeaways

  • Restart your computer completely and check that all cables are plugged in firmly before trying anything else.
  • Write down or photograph any error messages word-for-word, because they tell you what part of the system is failing.
  • Test one change at a time so you know which step actually fixed the problem.
  • If a program crashes repeatedly, uninstall and reinstall it rather than trying to repair it in place.
  • When nothing else works, booting into Safe Mode lets you run only essential programs and can reveal whether a background app is causing the crash.

Narrow down whether the problem is software or hardware

A software problem affects a single program or the operating system itself. A hardware problem affects the physical machine—the hard drive, memory, power supply, or motherboard. The way to tell is to see whether the problem happens in one program only or everywhere. If your web browser freezes but other programs work fine, that is a software problem with the browser. If your entire computer becomes unresponsive or shuts down without warning, that is likely hardware.

Test this by opening a different program and trying the same action. If you cannot save a file in one word processor, try saving in another program or in a text editor. If the problem follows you from program to program, it is a system-level issue. If it stays in one program, uninstall and reinstall that program first—this fixes corrupted files that cause crashes. Restart the computer after reinstalling before you test again.

Fix internet and network problems

If your internet is slow or disconnected, restart your modem and router. Unplug the modem from power, wait 30 seconds, and plug it back in. Do the same for your router 30 seconds later. This forces them to reconnect to your internet service provider. Wait two to three minutes for them to fully boot before testing your connection.

If restarting does not work, check that your computer is connected to the correct network. On Windows, click the network icon in the bottom right corner of the taskbar. On Mac, click the Wi-Fi icon in the top right corner of the menu bar. You should see your network name listed and marked as "Connected." If you see "No Internet" or a different network name, click your correct network and enter the password if prompted. If you cannot see your network at all, your Wi-Fi adapter may be off—look for a physical switch or key combination (often Fn plus a key with a Wi-Fi symbol) to turn it back on.

If you are connected but the internet is still slow, restart your computer. If it remains slow only on one device, the problem is with that device's connection, not your internet service. Move closer to the router to rule out distance or obstacles. If the problem is slow internet on all devices, contact your internet service provider—the issue is on their end.

Solve freezing and crashing with Safe Mode and Task Manager

When your computer freezes or a program becomes unresponsive, use Task Manager (Windows) or Activity Monitor (Mac) to close just that program without restarting the whole machine. On Windows, press Ctrl + Shift + Esc. On Mac, press Command + Option + Esc. Find the program that is not responding, select it, and click "End Task" or "Force Quit." The program will close and you can reopen it.

If your entire computer freezes and you cannot open Task Manager, hold the power button for 10 seconds until it shuts down completely. This is a hard shutdown and should be a last resort, but it is better than leaving the computer frozen. After it powers off, wait 30 seconds and turn it back on normally.

If a program crashes repeatedly even after reinstalling, boot into Safe Mode to see if the problem goes away. Safe Mode runs only the essential programs your computer needs to start, which helps you figure out if a background app is causing the crash. On Windows 10 or 11, restart your computer and press F8 repeatedly as it boots, or go to Settings > System > Recovery and click "Restart now" under Advanced Startup. On Mac, restart and hold Shift until you see the login screen. If the program works fine in Safe Mode, a background app or driver is interfering—restart normally and uninstall any recently added software.

Free up storage space when your computer slows down

A full hard drive makes your computer slow because it has no room to create temporary files while programs run. Check how much space you have left. On Windows, open File Explorer, right-click "This PC," and click "Properties." Look for the bar showing disk space used and free. On Mac, click the Apple menu, select "About This Mac," and click "Storage." If the free space is less than 10 percent of your total drive size, you need to delete files.

Start by emptying your Recycle Bin (Windows) or Trash (Mac)—files you delete do not actually disappear until you empty it. Then delete large files you no longer need: old video files, installer programs you have already installed, and duplicate photos. If you are not sure what to delete, look at your Downloads folder—it often contains old installers and files you downloaded once and never used again. Move important files to an external drive or cloud storage before deleting them if you want to keep them.

If you still need more space, uninstall programs you do not use. On Windows, go to Settings > Apps > Apps & Features, find the program, and click "Uninstall." On Mac, open Applications, drag unused programs to Trash, and empty Trash. Uninstalling removes the program files and frees up space, though it does not affect your documents or photos.

Update your operating system and drivers

Outdated software is a common cause of crashes and slow performance. Check for updates regularly. On Windows, go to Settings > Update & Security > Windows Update and click "Check for updates." On Mac, click the Apple menu, select "System Settings," click "General," and then "Software Update." Install any updates available and restart your computer when prompted. Updates often fix bugs that cause crashes and improve performance.

Drivers are the software that lets your operating system talk to hardware like your printer, graphics card, or network adapter. Outdated drivers can cause devices to stop working or behave unpredictably. On Windows, go to Device Manager by right-clicking the Start button and selecting it from the menu. Look for any devices with a yellow warning triangle—those need updated drivers. Right-click the device and select "Update driver," then choose "Search automatically for updated driver software." On Mac, drivers usually update automatically with the operating system, so check for system updates first.

Protect against malware and viruses

Malware and viruses can slow your computer, cause crashes, or steal your information. Windows comes with Windows Defender, which runs in the background automatically. On Mac, the built-in protections are usually enough for most users. To check that your protection is active, on Windows go to Settings > Privacy & Security > Windows Security and click "Virus & threat protection." You should see a green checkmark next to "Virus & threat protection." On Mac, go to System Settings > Privacy & Security and scroll down to see the security status.

If you think you have malware, run a full scan. On Windows, open Windows Security, click "Virus & threat protection," and under "Current threats" click "Scan options." Select "Full scan" and click "Scan now." This takes 30 minutes to an hour. On Mac, malware is less common, but you can use the free Malwarebytes tool to scan if you suspect a problem. Do not read security software from pop-up ads or unknown websites—these are often malware themselves. Stick with Windows Defender on Windows or the built-in protections on Mac.

Frequently Asked Questions

What should I do if my computer will not turn on at all?

Check that the power cable is plugged into both the computer and a working outlet. Try a different outlet to rule out a tripped circuit breaker. If the computer has a power button light, it should glow when plugged in. If nothing happens after 30 seconds, the power supply may have failed and you will need hardware service.

How do I know if my hard drive is failing?

A failing hard drive often makes clicking or beeping sounds, takes a very long time to open files, or causes frequent crashes. Run a hard drive test through your computer's built-in tools: on Windows, search for "Check Disk" and run it; on Mac, restart and hold Command + D to run the Disk Utility. If the test shows errors, back up your files when ready and have the drive replaced.

Why does my computer run slowly even after restart?

Slow performance usually comes from a full hard drive, too many programs running at startup, or malware. Check your storage first using the steps above. Then go to Settings > Apps > Startup (Windows) or System Settings > General > Login Items (Mac) and disable programs you do not need to run when the computer starts. If neither helps, run a malware scan.

Can I fix a blue screen of death on Windows?

A blue screen usually means a critical system error. Write down the error code shown on the screen. Restart your computer—if the blue screen does not return, the error was temporary. If it returns repeatedly, restart into Safe Mode and uninstall any recently installed software or drivers. If the problem persists, you may need to reinstall Windows or seek professional help.

What is the difference between restarting and shutting down?

Shutting down powers off the computer completely. Restarting powers it off and when ready turns it back on. Restarting clears more temporary files and resets connections, so it fixes more problems than shutdown alone. Always restart rather than just shut down when troubleshooting.