1. Restart it properly
It sounds too simple, but plenty of computers haven't truly restarted in weeks. In Windows 10 and 11, Shut down doesn't fully reset the system because of a feature called Fast Startup. Restart does. Click Start → Power → Restart, not Shut down, and see if things improve.
2. Find out what's using the computer
Press Ctrl + Shift + Esc to open Task Manager, then click the CPU, Memory and Disk column headings to sort by what's working hardest.
- If one program sits near the top using a lot, close it (right-click → End task) and see if the computer speeds up.
- If Memory is constantly above 85–90%, you're running more than the computer can handle. Close tabs and programs, or consider more RAM.
- If Disk sits at 100% for minutes at a time, that usually points to an old hard drive (see step 9).
3. Stop programs launching at startup
Many programs quietly add themselves to startup and run in the background all day. In Task Manager, open Startup apps and disable anything you don't need the moment you log in, like game launchers, music apps and "helper" tools. Keep your antivirus and anything you rely on (such as OneDrive) enabled.
4. Free up storage space
Windows slows down noticeably when the main drive is nearly full. Go to Settings → System → Storage. Aim to keep at least 15–20% free.
- Use Cleanup recommendations to remove temporary files and old Windows update files.
- Turn on Storage Sense to clear temporary files automatically.
- Move large photo and video folders to OneDrive or an external drive.
5. Uninstall programs you don't use
New computers often come loaded with trial software, and older ones collect years of apps. Go to Settings → Apps → Installed apps, sort by size and uninstall anything you don't recognise as needed. If you're unsure what something is, search the name before removing it.
6. Run Windows Update
Updates fix performance bugs as well as security holes. Go to Settings → Windows Update, install everything available and restart. Check Advanced options → Optional updates for driver updates too.
7. Scan for malware
Malware, adware and crypto-mining software can eat up processing power. Open Windows Security → Virus & threat protection → Scan options and run a Full scan. If something is found or you're still suspicious, run the Microsoft Defender Offline scan, which checks the computer before Windows fully loads.
8. Tame your web browser
For many people, "the computer is slow" really means "the browser is slow". Each open tab uses memory, and some extensions slow everything down.
- Close tabs you aren't using, or use your browser's tab sleeping feature.
- Remove extensions you don't recognise (Chrome:
chrome://extensions, Edge:edge://extensions). - Make sure the browser itself is up to date.
9. Check whether you have an SSD or an old hard drive
In Task Manager, click Performance and select your disk. It will say SSD or HDD. If it says HDD, that's very likely the main reason your computer is slow. Replacing a mechanical hard drive with a solid-state drive (SSD) typically makes startup and opening programs several times faster, and it's one of the most cost-effective upgrades available.
10. Check your power settings
Laptops often throttle performance to save battery. Go to Settings → System → Power & battery and set Power mode to Best performance when plugged in. On older laptops, a worn-out battery or overheating (a clogged fan) can also force the processor to slow down.
When it's time to call a technician
Get help if any of these apply:
- The computer is slow even after all the steps above.
- Disk usage sits at 100% or you hear clicking from the computer. A failing drive can take your files with it, so back up now.
- You see pop-ups, unfamiliar programs or browser redirects (signs of malware).
- The laptop is hot, the fan is loud, or it shuts down on its own.
- You're deciding whether to upgrade or replace and want an honest opinion.
An SSD upgrade, memory upgrade or clean-up often gives a three-to-five-year-old computer a genuinely useful second life. We'll tell you straight if it isn't worth it.
Quick answers
Why is my computer so slow all of a sudden?
A sudden slowdown is usually caused by a background update, a program stuck using the CPU or disk, a nearly full drive, or malware. Restart the computer, then check Task Manager to see what's using resources.
Is it worth upgrading an old computer to an SSD?
If the computer still has a mechanical hard drive and is otherwise in good condition, an SSD upgrade is usually the most cost-effective way to make it feel much faster.
Does Windows 10 still get updates?
Microsoft ended free security updates for Windows 10 on 14 October 2025. Computers that can run Windows 11 should be upgraded, and those that can't should be planned for replacement.