Start with the basics before you dig deeper

Most computer problems disappear after a restart. Before you assume something is broken, shut down completely (not sleep mode), wait 30 seconds, and turn it back on. This clears temporary files, resets connections, and stops runaway processes that slow things down or cause crashes.

If the problem persists, check the obvious things next: Is the power cable plugged in? Is the monitor cable connected? Are all the cables you can see actually seated firmly in their ports? Loose connections cause more problems than actual hardware failure. Push each cable in until you feel it click or seat fully.

For a laptop, plug it in and let it charge for at least 15 minutes before troubleshooting further. A drained battery can look like a dead computer. If you see a charging light on the power adapter or near the charging port, power is reaching the machine — it just needs time.

Key Takeaways

  • Restart your computer completely before troubleshooting anything else, because most problems clear on their own.
  • Check that all cables are pushed firmly into their ports, because loose connections are the most common cause of hardware problems.
  • Open Task Manager (Windows) or Activity Monitor (Mac) to see which programs are using the most resources and close the ones you do not need.
  • Update your operating system and drivers through the official settings menu, not from random websites, because outdated software causes crashes and slowdowns.
  • If a single program keeps crashing, uninstall it completely and reinstall it fresh, because corrupted files inside the program are usually the cause.

Identify what is actually broken by testing one thing at a time

When you say "my computer is slow" or "my computer is broken," you need to narrow down what is actually happening. Is the whole machine slow, or just one program? Does it freeze and then unfreeze, or does it stay frozen? Does it make any sounds — beeping, clicking, or fan noise? Does it show error messages? Write down exactly what you see, because that detail tells you where the problem is.

Test whether the problem happens in safe mode. On Windows, restart and hold F8 or Shift while it boots, then choose Safe Mode. On Mac, restart and hold Shift. Safe mode loads only the essential software, so if the problem goes away, something you installed is causing it. If the problem happens in safe mode too, the issue is in Windows or macOS itself, or in your hardware.

If one program keeps crashing but others work fine, the problem is almost always that program, not your computer. Uninstall it completely (use Control Panel on Windows, or Applications folder on Mac), restart, and reinstall it fresh from the official website. Corrupted files inside the program are usually the cause, and a fresh install fixes it.

Check what is using your computer's resources

A slow computer is usually a computer that is working too hard. Open Task Manager on Windows by pressing Ctrl+Shift+Esc, or on Mac open Activity Monitor from Applications > Utilities. Look at the CPU and Memory columns. If one program is using 80% or more of either, that program is the problem.

Close programs you are not using. If a program uses a lot of resources even when you are not actively using it, uninstall it. Antivirus software, browser extensions, and cloud backup programs are common culprits. You do not need five antivirus programs running at once — Windows comes with Windows Defender built in, and that is enough for most people.

If you see a program you do not recognize using resources, search for its name online before you close it. Some programs have names that do not match what they do. If it is something you installed and do not need, uninstall it. If it is a Windows system process and you are not sure, leave it alone and restart instead.

Update your operating system and drivers

Outdated software is a common cause of crashes, slowdowns, and security problems. On Windows, go to Settings > Update & Security > Windows Update and click Check for Updates. Let it install everything and restart if it asks. On Mac, go to System Preferences > Software Update.

Drivers are the software that lets Windows or macOS talk to your hardware — your graphics card, sound card, network adapter, and so on. Outdated drivers cause crashes and performance problems. On Windows, go to Device Manager (right-click the Start button), find the device that is giving you trouble, right-click it, and choose Update Driver. Choose "Search automatically for updated driver software." On Mac, drivers usually update with the operating system, so if you are up to date on macOS, your drivers are current.

Never read drivers from random websites. Always get them from the manufacturer's official website or through Windows Update. Fake driver websites are a common way malware gets onto computers.

Clear out temporary files and free up disk space

A full hard drive makes everything slow. On Windows, go to Settings > System > Storage and see how much space you have left. If you have less than 10% free, you need to delete something. Start by emptying the Recycle Bin, then uninstall programs you do not use (Settings > Apps > Apps & Features).

You can also use Disk Cleanup. Press Windows key + R, type cleanmgr, and press Enter. Check the boxes for Temporary Files, Recycle Bin, and Downloads, then click Delete Files. This removes files Windows does not need anymore.

On Mac, go to Apple menu > About This Mac > Storage. Click Manage to see what is taking up space. Delete old downloads, empty the Trash, and uninstall programs you do not use by dragging them to Trash from the Applications folder.

Check for malware and viruses

Malware and viruses cause slowdowns, crashes, pop-ups, and unexpected behavior. Windows Defender (built into Windows) and macOS's built-in security are usually enough, but you can run a deeper scan if you suspect infection.

On Windows, open Windows Security (search for it in the Start menu), go to Virus & threat protection, and click Scan options. Choose Full scan and click Scan now. This takes a while but checks every file on your computer. On Mac, malware is less common, but you can read Malwarebytes (free version) and run a scan if you are concerned.

If you see pop-ups, unexpected toolbars in your browser, or your home page changed without you doing it, you likely have adware. Uninstall any programs you do not recognize from Settings > Apps on Windows or Applications on Mac. Check your browser extensions too — go to your browser settings and remove anything you did not install.

Know when to call a professional

If your computer makes clicking or beeping sounds, does not turn on at all, or shows a blue or black screen with error codes, the problem is likely hardware and you should stop troubleshooting. Clicking usually means a failing hard drive. A computer that will not turn on could be a power supply, motherboard, or battery. These are not things you can fix with software.

If you have tried restarting, checking cables, running Task Manager, updating software, and clearing space, and the problem is still there, write down exactly what happens and take the computer to a repair shop. Bring a list of what you have already tried — that saves them time and saves you money.

If you are not comfortable opening Task Manager or changing settings, that is fine. A local computer repair shop can do this work for you. It usually costs between $50 and $150 for a diagnostic, and they can tell you whether the fix is worth doing.

Frequently Asked Questions

Why does my computer run slow even after I restart it?

Restart clears temporary problems, but if slowness comes back, something is using resources constantly. Open Task Manager and look for programs using high CPU or memory. Uninstall programs you do not need, update your operating system, and make sure you have at least 10% free disk space. If one program is always the culprit, uninstall and reinstall it.

What does it mean if my computer freezes and then unfreezes?

Freezing usually means something is using all your computer's resources for a moment. Check Task Manager to see what program spikes when it happens. It could also be a failing hard drive — if freezing happens randomly and gets worse over time, back up your files and take the computer to a repair shop.

Is it safe to delete files in Disk Cleanup?

Yes, Disk Cleanup only removes temporary files that Windows does not need. It will not delete your documents, photos, or programs. The only exception is Downloads — if you have files in your Downloads folder you want to keep, move them somewhere else first.

How do I know if I have a virus?

Signs include unexpected pop-ups, your browser home page changing, programs running slowly, or programs crashing. Run a full scan with Windows Defender or Malwarebytes. If malware is found, the scan will remove it. If you see no malware but problems continue, the issue is probably not a virus.

Can I fix a computer that will not turn on?

Check that the power cable is plugged in firmly and the outlet works (plug a lamp into it to test). If it still will not turn on, the power supply, battery, or motherboard may be failing. This is not something software troubleshooting can fix — take it to a repair shop.