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A slow computer is one of the most frustrating everyday tech problems — and the good news is you can usually fix it yourself in an afternoon, without paying anyone. Below are seven fixes in order, from the quickest free ones to the upgrades worth paying for. Work down the list and stop when your computer feels fast again.
1. Restart your computer (yes, really)
If your computer has been on for days or weeks, background processes and memory leaks pile up and slow everything down. A full restart clears them out. Do this first — it fixes more slowdowns than people expect, and it costs nothing.
2. Free up disk space (the most common cause)
When your hard drive gets close to full, Windows and Mac both slow to a crawl. If you have less than about 10–15% free space, this is very likely your problem. The trick is finding what is actually using the space, because it is usually hiding in folders you never look at.
The fastest free way to see this on Windows is a tool called WizTree. It scans your entire drive in seconds and shows you the biggest files and folders at a glance, so you know exactly what to clean up. It is free for personal use.
- Windows: download WizTree (free) from diskanalyzer.com, run it, and sort by size. TreeSize Free and the classic WinDirStat are good alternatives.
- Mac: use the built-in storage view (Apple menu → About This Mac → Storage → Manage), or a tool like DaisyDisk.
Once you can see the big stuff, delete what you do not need (old downloads, installers, duplicate videos) and move things you rarely use — like photos and old projects — to a backup before deleting.
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3. Cut down startup programs
Lots of apps quietly launch when you boot, dragging out startup and eating memory. On Windows, open Task Manager (Ctrl+Shift+Esc) → Startup tab → disable anything you do not need at boot. On Mac, go to System Settings → General → Login Items.
4. Uninstall programs you never use
Old software takes up space and sometimes runs in the background. Remove anything you have not opened in a year. Windows: Settings → Apps → Installed apps. Mac: drag apps from Applications to the Trash.
5. Scan for malware
A sudden, severe slowdown can be a sign of malware running in the background. Run a full scan with a reputable security tool. Windows includes Microsoft Defender for free, which is a solid first check.
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6. Add more memory (RAM)
If your computer is a few years old and chokes when you open lots of browser tabs or apps, more RAM is the most cost-effective upgrade you can make. On many laptops and desktops it is a quick, do-it-yourself job. Check how much RAM your model supports before buying.
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7. Upgrade to an SSD (the biggest speed boost)
If your computer still uses an old spinning hard drive (HDD), switching to a solid-state drive (SSD) is the single biggest speed improvement you can buy. It makes an old machine feel brand new — faster boot, faster apps, faster everything.
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The bottom line
Most slow computers speed up dramatically without spending much — or anything at all. Start with the free fixes: restart, free up disk space with WizTree, trim your startup programs, and remove unused apps. Only spend money on RAM or an SSD if you still need more speed after that. Either way, you now know exactly where to look.
Want to keep your computer fast for good? Read our guide on how to back up your files so you can clean up with confidence.