By The KTech team · Published 29 October 2026
A laptop rarely goes slow overnight. More often it drifts: a few extra seconds to start up, a spinning circle when you open email, fans roaring while you read a web page. By the time it is properly annoying, there is usually more than one cause behind it.
These are the eight causes we meet most often in our Kingsbridge workshop, followed by the safe checks you can do yourself and a straight answer on when a repair or a replacement makes sense.
The eight usual suspects
- A nearly full drive. Windows and macOS need breathing space to work. When the drive is more than about nine-tenths full, everything slows down, from updates to opening a document.
- An old spinning hard drive. Laptops built before about 2017 often still have one. They are far slower than modern solid-state drives and tend to get worse with age.
- Too many startup programmes. Every app that launches itself at sign-in takes memory and processing time before you have even opened anything.
- Overheating. Dust in the vents, a laptop used on a duvet or a lap, and old thermal paste all make the machine throttle itself to stay cool.
- Malware and unwanted add-ons. Browser extensions, pop-up injectors and the occasional proper infection quietly use up resources in the background.
- Updates stuck or half-finished. A failed update can leave a machine trying, and failing, to finish a job every time it starts.
- Not enough memory. Modern browsers with plenty of tabs, plus a few other programmes, can easily outgrow a laptop with 4GB of RAM.
- Plain age. After six or seven years, the processor and the rest of the hardware simply cannot keep up with what today's software expects.
Safe checks you can do yourself
Start with the simple things. Restart the laptop properly (a full shut down and start, not just closing the lid) and see whether it feels different. Many machines are left asleep for weeks, and a restart clears a surprising amount.
Next, look at how full the drive is. On Windows, open File Explorer and look at This PC; on a Mac, check Storage in System Settings. If you are close to full, move photos and old downloads to an external drive or cloud storage before deleting anything you are unsure about.
Open Task Manager on Windows (Ctrl, Shift and Esc together) or Activity Monitor on a Mac, and look at what is using the most memory or processor time. If one thing is constantly near the top and you do not recognise it, that is worth a note for later, but please do not delete things you cannot identify.
Feel the laptop. If it is hot to the touch and the fan never settles, take it off soft surfaces, give the vents a gentle blast of air with the laptop switched off, and see whether it improves. Opening the case is a job for a workshop.
Finally, make sure Windows or macOS is up to date and that your security software is working. Try a different browser, too. If only one browser is slow, the cause is probably an extension rather than the laptop itself.
Things we would avoid
Be wary of 'PC speed-up' programmes and websites that scan your machine and then demand payment. Many of them make the problem worse or install extras you never asked for. If a pop-up tells you your computer is infected and tells you to ring a number, close it and do not call. Our guide to virus and malware removal explains what to do next.
Also resist the temptation to keep resetting or reinstalling without a backup. Photos, documents and saved passwords can disappear in a moment.
Repair, upgrade or replace?
The good news is that many slow laptops can be brought back to life without much fuss. Swapping an old hard drive for a solid-state drive is the single biggest improvement we can make, and adding memory helps when there is room for it. A thorough clean of the fans and a fresh application of thermal paste often cures overheating.
A repair makes sense when the laptop is otherwise sound: a good screen, a decent keyboard, a battery that still holds a charge, and a processor from the last six or seven years. It makes less sense when the hardware is very old, when several parts are failing at once, or when the machine cannot run a supported version of Windows. In those cases, a refurbished or new replacement will serve you better, and we will say so plainly.
Wherever you end up, your files matter more than the machine. We always check that your data is safe, or copied somewhere safe, before we change anything.
Getting it looked at locally
If you would like a second pair of eyes, our workshop handles computer and laptop repair for homes and small businesses, and we explain what we find in plain language before any work starts. People bring us machines from all over the area, and laptop repair in Kingsbridge is a short trip for many of our customers.
A few questions we hear often
Will a factory reset fix it? Sometimes, but it is a blunt tool. A reset wipes your files and settings, and if the real cause is a failing drive or overheating, the laptop will be slow again within days. We prefer to find the cause first and reset only when it makes sense, with your data safely copied elsewhere.
Is it worth adding more memory? If your laptop has 4GB and you keep many browser tabs open, yes, it often helps noticeably, provided the memory is not soldered to the board. Many thin laptops have it fixed in place, and in that case a replacement or a different fix is the better route.
Why did it get slow after an update? Large updates can use the drive heavily for a day or two while they finish tidying up in the background. If the slowness is still there after a few restarts, or the update never completed, something else is going on and it is worth a look.
Could it just be the battery? An old battery can make a laptop throttle itself when it is unplugged, so if it is fast on the mains and sluggish on battery, say so when you bring it in. It is a useful clue, and a battery is one of the simpler parts to replace.
How long will a repair take? It depends on the cause and on whether parts are needed. We will tell you what we expect once we have looked, rather than guessing in advance.