A slow computer is rarely "just old." It is usually one of a handful of specific problems, and you can check most of them yourself in under half an hour. Work through these in order — most people find their fix before the halfway mark.
For what it's worth, this checklist is roughly what a big-box store sells as a tune-up. Geek Squad's published rate for a PC tune-up and cleaning was $49.99 as of September 2026 — a fair price if you want a storefront to walk into, but nothing below needs a counter and a queue.
1. Restart it properly
Not sleep, and on Windows, not "Shut down" either. Windows ships with Fast Startup enabled, which means shutting down actually hibernates part of the system and brings it back at the next boot, glitches included. Click Restart — that is the only option that truly starts fresh. Macs are simpler: Apple menu, then Restart. Both systems keep programs half-alive for weeks, so if your machine has not genuinely rebooted in a while, do this first and see how it feels.
2. See what is eating the machine
On Windows press Ctrl+Shift+Esc to open Task Manager; on a Mac open Activity Monitor from Applications > Utilities. Sort by CPU, then by Memory. You are looking for one item pinned near the top — a stuck updater, an antivirus mid-scan, a video call app that never really hung up. One runaway process explains a lot of "slow computers," and ending it, or uninstalling the program behind it, is often the whole fix.
If the machine is slow before you even sign in, the culprit is more likely the startup list, the disk, or the hardware — keep going.
3. Tame your browser
If the top of that list is your browser, the browser is the computer's problem. Every open tab is a running program, and a few dozen of them will use more memory than everything else combined. Close what you are not reading — bookmarks exist for the tabs you are keeping "just in case." Chrome and Edge both have a memory-saver setting that puts idle tabs to sleep; turn it on. And look at your extensions, because it takes one badly written coupon finder to slow every page you load.
4. Let the sync clients finish
OneDrive, Dropbox, Google Drive and iCloud do their heavy lifting silently. After a new sign-in, a big photo import, or a restore, the client can spend hours hashing and uploading files, and the disk churn makes everything else crawl. Click the little cloud icon near the clock and read its status. "Processing changes" for days means a stuck client — pause syncing, restart, resume. The same goes for search indexing: Windows Search and Spotlight both rebuild after big updates, and the kindest thing is to leave the machine on overnight and let them finish.
5. Free up disk space
A drive that is more than about 90% full slows everything down — Windows and macOS need free space to work in, and even SSDs get slower as they fill. On Windows, Settings > Storage shows what is taking the room, and Storage Sense will clear temporary files for you. On a Mac it is System Settings > General > Storage. Empty Downloads, empty the trash, and uninstall the programs you have not opened this year. Do not buy a "cleaner" app for this; the built-in tools do the job.
6. Trim the startup list
In Task Manager's Startup tab (or System Settings > General > Login Items on a Mac), disable everything you do not recognize as essential. Each entry loads at boot and then sits in memory all day. Printer helpers, chat apps, game launchers and updaters all sneak in. Disabling them does not uninstall anything — it just stops them starting themselves.
7. Scan for malware
Unwanted software mining or spying in the background is a classic cause, and it does not announce itself. Run a full scan with Windows Security or a reputable scanner — not a random "PC cleaner" ad, which is often the problem itself. If the scan finds something, or the machine is throwing pop-ups you never asked for, follow the ordered steps in our virus guide before doing anything else.
8. Feel for heat
Processors deliberately slow themselves down when they run hot — thermal throttling — and it turns a fast laptop into a slow one without a single error message. The tells: the fan is always loud, the keyboard deck is warm, and the slowdown arrives minutes into work rather than at boot. Dust-clogged vents, a laptop used on a duvet, or dried-out thermal paste in an older machine are the usual causes. The overheating guide walks through each fix.
9. Rule out a failing drive
If the machine is slow AND you hear clicking, see files disappearing, or get freezes measured in minutes: stop and back up your files now. Older spinning drives fail slowly, then all at once, and every extra hour of use is a gamble. The warning signs are listed here — check them before you continue, because everything else on this list can wait and a dying drive cannot.
10. The upgrade that changes everything
If your computer still has a spinning hard drive, replacing it with an SSD is the single biggest speed fix that exists. Boot times drop from minutes to seconds and every program opens faster, because the drive was the bottleneck all along. The part costs a fraction of a new computer; the labor is an hour or two for a technician who does it weekly. Pair it with a RAM bump if you have 4GB — 8GB is the realistic floor for Windows 11 and modern browsers — and a machine from 2017 can feel new again. A tech on Koadi can tell you over a screen-share whether your exact model is worth upgrading before you spend anything.
Repair or replace: the honest math by age
Age decides more than any benchmark. As a working rule:
- Under 4 years old: fix it. Almost nothing on this list justifies replacing a machine this young, and most of the fixes above are free.
- 4–7 years old: upgrade it if the bones are good. An SSD and more RAM cost far less than a new computer and solve the actual problem. Check the Windows question first, though — a machine that cannot run Windows 11 is on borrowed time, and that decision has its own guide.
- 8 years or older: put the money toward a replacement. At this age the screen, battery, ports and motherboard are all queuing up to be the next failure, and repair spending rarely comes back. Typical repair costs are here if you want to run the numbers on your machine.
One rule cuts across all three ages: whatever you decide, get your files off it first.
If you'd rather skip to the part where it's fixed
Working the list takes an afternoon; describing the problem takes two minutes. Post it free at Koadi in plain words — "slow since June, fan always on" is plenty — and vetted, identity-verified technicians will pick it up. You set a fixed price or take bids, and your payment sits in escrow until you approve the fix, so nobody gets paid for a computer that is still slow. Most slowness is solved remotely over a screen-share, evenings and weekends included, anywhere in the US — and if it turns out to be an SSD swap or a dust-clogged fan, a local technician can come to you.