"It's gotten so slow" is probably the thing I hear most often. The good news is that a slow computer is usually not a broken one, and a lot of the fixes are free. Here's what I'd try, roughly in the order I'd try it: quickest and easiest first.
1. Actually restart it
On Windows 10 and 11, "Shut down" doesn't always clear everything out, because of a feature called Fast Startup. "Restart" does. If the computer has been on (or asleep) for days or weeks, a proper restart alone can make a real difference.
2. Cut down what starts with Windows
Lots of programs quietly add themselves to startup and then sit in the background using memory. Press Ctrl + Shift + Esc to open Task Manager and go to Startup apps (just "Startup" on Windows 10). Disable anything you don't need the moment the computer turns on: chat apps, game launchers, updaters. It doesn't uninstall them, they just won't start on their own. If you're not sure what something is, leave it alone.
3. Free up some disk space
A drive that's almost full slows everything down. Go to Settings > System > Storage and look at the cleanup recommendations, and consider turning on Storage Sense so Windows tidies up temporary files on its own. Then uninstall programs you no longer use, and move old photos and videos to an external drive or the cloud (ideally as part of a proper backup).
4. Look at your browser
Often it's not "the computer", it's the browser. Every open tab uses memory, and some extensions use a lot more than you'd expect. Close the tabs you don't need, and remove extensions you don't recognise or never use. If the browser itself feels sluggish, updating it usually helps too.
5. Let Windows Update finish
Go to Settings > Windows Update and install whatever is waiting, then restart. Updates running in the background can slow things down while they work, and leaving them half-done for weeks doesn't help either.
6. Check for malware
You don't need to buy anything for this. Open Windows Security, go to Virus & threat protection > Scan options and run a Full scan. It takes a while, so start it when you don't need the computer. Pop-ups you didn't ask for, a browser homepage that changed on its own, or programs you don't remember installing are all good reasons to do this sooner rather than later.
7. Hard drive or SSD?
In Task Manager, open the Performance tab and click on your disk: it will say SSD or HDD. If it's an HDD (a traditional spinning hard drive), that's very often the main reason the computer feels slow, especially at startup. Swapping it for an SSD is usually the single biggest improvement you can make to an older computer, and it costs a lot less than a new one.
8. Is it running out of memory?
On the same Performance tab, check Memory while you're doing what you normally do. If it's constantly near the top, more RAM will help, as long as your computer has room for it. Not every laptop can be upgraded, so it's worth checking before buying anything.
When it's time to get help
If you've been through all of this and it's still slow, or it's slow alongside other symptoms like loud fans, strange noises or random shutdowns, it may be a hardware problem rather than clutter. The signs your computer needs a repair are worth a read, and the troubleshooting wizard can help narrow things down.
And if you're wondering whether an old machine is still worth the money, the repair-or-replace calculator gives you an honest starting point. Sometimes an SSD and a clean-up gives a computer years more. Sometimes it really is time for a new one, and I'll tell you which.
Get in touch and I'll take a look at what's slowing it down →