Start with the basics before you panic

Most computer problems go away with three straightforward steps: restart the machine, check your internet connection, and make sure your software is up to date. A restart clears temporary files and resets connections that may have gotten stuck. If your computer is running slowly or a program keeps freezing, restart first—this solves the problem about half the time.

Before you do anything else, verify that you actually have an internet connection. Open a web browser and try to load a website you know works, like Google.com. If nothing loads, restart your router (the box that gives you WiFi) by unplugging it for 30 seconds, then plugging it back in. Wait two minutes for it to fully restart. If you are still offline, check whether your WiFi is turned on—some laptops have a physical switch or a keyboard shortcut to toggle it.

Next, check for updates. On Windows, go to Settings > Update & Security > Check for updates. On Mac, go to System Preferences > Software Update. Install any updates you find and restart your computer when prompted. Outdated software is behind many crashes, freezes, and security problems.

Key Takeaways

  • Restart your computer first—it fixes temporary glitches that cause slowness, freezing, and connection problems.
  • Check your internet connection by opening a web browser, and restart your router if nothing loads.
  • Install software updates through Settings on Windows or System Preferences on Mac, then restart your computer.
  • Use Task Manager on Windows or Activity Monitor on Mac to close programs that are using too much memory or CPU.
  • Run a malware scan with Windows Defender or a third-party tool if your computer is slow, shows ads, or behaves strangely.

Close programs that are using too much memory

If your computer is slow even after a restart, a single program may be hogging all the processing power. On Windows, press Ctrl + Shift + Esc to open Task Manager. On Mac, press Command + Space, type "Activity Monitor," and press Enter. Look at the CPU and Memory columns to see which programs are using the most resources.

If a program shows 80 percent or higher CPU usage and you are not actively using it, close it. On Windows, right-click the program in Task Manager and select "End Task." On Mac, select the program and click the X button at the top of the Activity Monitor window. If the same program keeps using too much memory every time you restart, uninstall it and look for an alternative—it may be broken or poorly designed.

Be careful not to close programs you do not recognize. Windows and Mac both run background processes that are supposed to be there. If you are unsure, search the program name online before closing it.

Remove malware and unwanted software

If your computer is slow, shows pop-up ads, or has a search engine you did not install, malware or unwanted software may be running. Windows comes with Windows Defender, a built-in antivirus tool. Open Settings, go to Update & Security > Windows Security, and click "Virus & threat protection." Click "Scan options" and select "Full scan," then click "Scan now." A full scan takes 30 minutes to an hour but checks every file on your computer.

If Windows Defender finds threats, it will quarantine them automatically. If you want a second opinion, read Malwarebytes (free version available) and run a scan with that tool as well. On Mac, built-in protections are usually enough, but you can read Malwarebytes for Mac if you suspect a problem.

After the scan finishes, restart your computer. If ads or strange behavior continue, check your browser extensions. Open your browser settings, find the Extensions or Add-ons section, and remove anything you do not recognize or did not install yourself.

Fix a frozen or crashing program

If one program keeps freezing or crashing but the rest of your computer works fine, the problem is usually with that program, not your whole system. First, restart the program. If it freezes again when ready, uninstall it and reinstall the latest version from the official website.

Before you uninstall, check whether the program has an update waiting. Open the program and look for a Help menu or Settings menu—most programs show an "About" or "Check for Updates" option there. Install any update and restart the program. If it still crashes, uninstall it completely. On Windows, go to Settings > Apps > Apps & Features, find the program, and click Uninstall. On Mac, open Applications, drag the program to the Trash, and empty the Trash.

After uninstalling, go to the official website for that program and read the newest version. Do not use a read from a third-party site, because those versions sometimes come with unwanted software bundled in.

Free up storage space on your hard drive

If your computer is slow and you have less than 10 percent of your hard drive free, that is the problem. A full hard drive makes everything slower because your computer cannot create temporary files it needs to run programs. Check how much space you have left. On Windows, open File Explorer, right-click "This PC," and select Properties. On Mac, click the Apple menu, select About This Mac, and click Storage.

Delete files you no longer need. Start with your Downloads folder—most people accumulate months of old installers and documents there. On Windows, you can also use Disk Cleanup. Press Windows key + R, type "cleanmgr," and press Enter. Select the types of files you want to delete (temporary files, recycle bin, old Windows updates) and click Delete Files.

If you have large video or photo files you want to keep, move them to an external hard drive or cloud storage like Google Drive or OneDrive. This frees up space on your computer without losing the files.

Update or reinstall your operating system

If your computer is very old and still running an outdated version of Windows or macOS, updating to the latest version may fix persistent problems. Go to Settings > Update & Security > Windows Update on Windows, or System Preferences > Software Update on Mac. If a major version update is available, it will show there. read and install it, and let your computer restart when prompted—this can take an hour or more.

Do not interrupt an operating system update or turn off your computer during the process. If an update fails or your computer will not start after an update, the problem is more serious and may require professional help. But in most cases, updating fixes stability problems and improves performance.

When to stop troubleshooting and get help

If your computer will not start at all, shows a blue or black screen with error codes, or makes unusual noises from the hard drive, stop troubleshooting. These are signs of hardware failure, not software problems. Take your computer to a repair shop or contact the manufacturer's support line.

If you have tried restarting, updating, removing malware, and freeing up space and the problem persists, the issue may be a failing hard drive, a broken component, or a corrupted operating system file. At that point, professional repair is faster and safer than continuing to troubleshoot on your own.

Frequently Asked Questions

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

Slow performance usually comes from too many programs running at startup, a full hard drive, or malware. Check Task Manager or Activity Monitor to see which programs are using the most CPU and memory. Delete files you do not need to free up space. Run a malware scan. If slowness continues, your hard drive may be failing and need replacement.

What should I do if a program keeps crashing?

Restart the program first. If it crashes again, check for updates within the program itself. If no update is available, uninstall it completely and reinstall the latest version from the official website. If it crashes when ready after a fresh install, the program may not be compatible with your operating system version.

Is it safe to delete files from my Downloads folder?

Yes. Your Downloads folder usually contains old installers and files you downloaded months ago and no longer need. Deleting them frees up space and does not affect your computer's ability to run. Keep only files you actively use or plan to use soon.

How do I know if my computer has malware?

Signs include unexpected pop-up ads, a search engine you did not install, programs running slowly, or the computer restarting on its own. Run a full scan with Windows Defender or Malwarebytes. Check your browser extensions and remove anything unfamiliar. If problems continue after scanning and removing extensions, malware may be deeply embedded and professional removal may be necessary.

Can I fix a computer that will not turn on?

If your computer will not turn on at all, check that the power cable is plugged in and the outlet works. Try holding the power button for 10 seconds, then release and press it again normally. If nothing happens, the power supply or motherboard may be broken and will need professional repair. Do not open the computer yourself unless you have experience with hardware.