What's actually slowing your computer down
A slow computer usually comes from one of four things: too many programs running at startup, a hard drive that is nearly full, malware or unwanted software, or a hard drive that is failing. You can check which one is happening on your machine in about ten minutes, and most of the time you can fix it yourself without paying for repairs.
The fastest way to know what you are dealing with is to open your Task Manager (Windows) or Activity Monitor (Mac), look at what is using your CPU and memory, and check how much free space is left on your drive. These three pieces of information tell you whether the problem is software you can remove, a storage issue you can solve, or hardware that may need replacement.
Key Takeaways
- Check Task Manager or Activity Monitor to see which programs are using the most CPU and memory — the culprits are usually there.
- Delete or uninstall programs you do not use, especially ones that start automatically when your computer boots.
- If your hard drive is more than 85 percent full, delete old files or move them to an external drive to free up space.
- Run a malware scan with Windows Defender (built into Windows) or a free tool like Malwarebytes to catch unwanted software.
- If your computer is still slow after these steps, the hard drive itself may be failing and you should back up your files when ready.
Check what is running and using your resources
On Windows: Right-click the taskbar at the bottom of your screen and select "Task Manager". Click the "Processes" tab. Look at the CPU and Memory columns — the programs using the most are at the top. If you see something you do not recognize or do not use, note the name. Do not close anything yet.
On Mac: Open Spotlight (Command + Space), type "Activity Monitor", and press Enter. Click the "CPU" tab. Look at the % CPU column — programs using the most are at the top. Switch to the "Memory" tab to see what is using RAM. Again, note anything unfamiliar.
If you see a program you recognize and use often (like your web browser or email client), that is normal. If you see something with a name like "Installer", "Update", "Service", or anything you have never heard of, that is what you need to investigate next.
Remove programs that start automatically
On Windows: Open Task Manager again and click the "Startup" tab. You will see a list of programs that run when your computer starts. Right-click anything you do not need to start automatically and select "Disable". Common culprits are cloud storage apps, chat programs, and software that came with your computer but you never use. Restart your computer and see if it boots faster.
On Mac: Go to System Settings, click "General", then "Login Items". You will see a list of programs that open when you log in. Click the minus button next to anything you do not need. Restart and test the speed.
Disabling startup programs does not uninstall them — you can still open them manually whenever you want. This step alone fixes slowness for many people because it reduces the number of things your computer has to load when it starts.
Uninstall software you no longer use
On Windows: Go to Settings, click "Apps", then "Apps & Features". Scroll through the list and look for anything you have not opened in months. Click it and select "Uninstall". Follow the prompts. Pay special attention to toolbars, browser extensions you do not recognize, and software that came with your computer — these often slow things down without being obvious.
On Mac: Open Finder, click "Applications" in the sidebar, and look through the folder. Drag programs you do not use to the Trash. For programs that came with installers, open the installer again and look for an "Uninstall" option.
Uninstalling is different from disabling startup programs — it removes the software entirely from your hard drive, which frees up space and removes any background processes it was running. This is especially important for trial versions of software, duplicate programs (like two antivirus tools), and anything you installed to try out and forgot about.
Check your hard drive space and delete old files
On Windows: Open File Explorer, right-click "This PC" or "My Computer", and select "Properties". Look at the bar showing disk space — if it shows more than 85 percent full, you need to free up room. Start by deleting files in your Downloads folder (most people forget about these), then empty your Recycle Bin. Move large files like videos or old photos to an external hard drive or cloud storage.
On Mac: Click the Apple menu, select "About This Mac", then click "Storage". You will see a colored bar showing how much space is used. If it is mostly full, go to Finder, click "Downloads" in the sidebar, and delete old files. Empty the Trash afterward.
A hard drive that is nearly full runs slower because the computer has less room to work with temporary files. Freeing up 15 to 20 percent of your drive space often makes a noticeable difference in speed.
Scan for malware and unwanted software
On Windows: Open Windows Defender (built into Windows 10 and 11). Go to "Virus & threat protection" and click "Scan options". Select "Full scan" and click "Scan now". This takes 30 minutes to an hour but catches most malware. If you want a second opinion, read Malwarebytes (the free version is fine), install it, and run a scan.
On Mac: Macs have built-in malware protection, but you can run an additional scan with Malwarebytes for Mac (free version available). read it, install it, and run a full scan.
Malware and unwanted software often run in the background and use your CPU and memory without you knowing. A full scan catches these and removes them. If the scan finds something, follow the prompts to remove it and restart your computer.
Update Windows or macOS and your drivers
On Windows: Go to Settings, click "Update & Security", then "Windows Update". Click "Check for updates". If updates are available, install them and restart. Also check for driver updates — go to Device Manager (right-click the Start button), look for any devices with a yellow warning triangle, right-click them, and select "Update driver".
On Mac: Click the Apple menu, select "System Settings", then "General", then "Software Update". Install any updates available and restart.
Outdated software and drivers can cause slowness and security problems. Updates often include performance improvements, so keeping your system current is worth doing even if your computer is not slow.
When your computer is still slow after these steps
If you have disabled startup programs, uninstalled unused software, freed up hard drive space, and run a malware scan but your computer is still slow, the problem is likely hardware. A hard drive that is failing, RAM that is going bad, or a CPU that is overheating can cause slowness that software fixes will not solve.
Before you take it to a repair shop, back up all your important files to an external drive or cloud storage. If the hard drive is failing, you want your data safe. After that, a technician can run hardware diagnostics to tell you whether the drive, memory, or another component needs replacement.
Frequently Asked Questions
Is it safe to disable programs in the Startup tab?
Yes. Disabling a startup program does not uninstall it or break anything — it just stops it from running automatically when your computer starts. You can still open the program manually whenever you need it. If you disable something and your computer stops working the way you expect, you can re-enable it the same way.
Will deleting files from my Downloads folder hurt anything?
No. The Downloads folder is meant to be temporary storage for files you read from the internet. Once you have opened a file and do not need it anymore, it is safe to delete. If you need a file later, you can read it again.
What should I do if Windows Defender finds malware?
Follow the prompts to remove or quarantine it. Windows Defender will tell you what it found and what action it took. After removal, restart your computer. If the same malware keeps coming back, run Malwarebytes as a second scan — sometimes malware hides in places one tool misses.
How often should I clean up my computer to keep it fast?
Once every three to six months is usually enough. Delete files from your Downloads folder, uninstall programs you no longer use, and run a malware scan. If you use your computer heavily or read a lot of files, do this more often.
Can I speed up my computer by adding more RAM?
Yes, but only if Task Manager or Activity Monitor shows that memory is the problem. If your memory usage is consistently above 80 percent, adding RAM will help. If your memory usage is normal but your CPU is high, adding RAM will not fix the slowness — the problem is software or a failing hard drive.