"It used to be fast" is probably the single most common thing we hear. The frustrating part, from the customer's side, is that nothing obviously changed — same computer, same programs, same person using it. But it now takes ninety seconds to open a browser.
A slow computer is a symptom, not a diagnosis. Underneath it there is almost always one of six specific causes, and they have very different fixes. Some cost nothing. One of them means the machine is dying. Being able to tell them apart is most of the job.
1. The machine still has a mechanical hard drive
This is the big one, and it accounts for more slow-computer jobs than the other five combined.
A traditional hard drive has a physical disc spinning inside it and an arm that moves across the surface to find data. A solid state drive (SSD) has no moving parts and reads data electronically. In everyday use an SSD is not slightly faster — it is somewhere between ten and fifty times faster for the kind of small, scattered reads that starting Windows and opening programs actually involve.
How to tell: if your computer was bought before roughly 2018, or was a budget model after that, there is a good chance it still has a mechanical drive. A machine that takes more than two minutes to become usable after you log in, and where the drive activity light stays solid the whole time, is the classic signature.
The fix: replacing the drive with an SSD and moving your data across. On a five-year-old laptop that feels unusable, this single change routinely takes startup from two minutes to fifteen seconds. It is the best value upgrade in computing and it is not close.
This is exactly the work covered by our backup and data transfer service.
2. Too much is starting up with the computer
Every program that offers to "start automatically so it is ready when you need it" is making a withdrawal from the same account. Individually none of them matter. Fifteen of them together mean your computer spends the first several minutes after login doing everyone else's work before it gets to yours.
How to tell: the computer is painful for the first few minutes and then becomes reasonably usable.
The fix: you can do this one yourself. On Windows, press Ctrl+Shift+Esc to open Task Manager, click the Startup tab, and look at the "Startup impact" column. Anything marked High that you do not recognise or do not need immediately can be disabled. Disabling a startup item does not uninstall the program — you can still open it normally.
Leave anything that is your antivirus, your touchpad or graphics driver, or anything from your computer's manufacturer that mentions power or battery.
3. The drive is nearly full
Both hard drives and SSDs slow down markedly as they approach capacity. Windows also needs free space to work in — for virtual memory, for updates, for temporary files. When free space drops below about 10 percent of the drive, everything gets worse at once.
How to tell: open File Explorer, click This PC, and look at the bar under your C: drive. If it is red, this is at least part of your problem.
The fix: the quick win is usually Windows' own Storage Sense, plus emptying the Recycle Bin, plus clearing your Downloads folder — which on most machines we see contains several years of installers nobody will ever open again. If photos and videos are the bulk of it, moving them to an external drive or cloud storage is the real answer, and it should be done as part of a proper backup rather than as a way to free up space. Those are different jobs and only one of them protects you.
4. Malware, or something close enough to it
Genuine viruses are less common than they were. What has replaced them is a grey category of software that is technically consensual and practically parasitic: browser toolbars, "PC optimisers" that create the problem they offer to solve, coupon finders, and adware bundled into the installer of something you did want.
How to tell: new toolbars in your browser, a search engine you did not choose, pop-ups outside the browser, or a fan that runs hard while you are doing nothing.
The fix: proper removal, not just an antivirus scan — most of this category is deliberately designed not to trigger antivirus. Our virus and malware removal service covers the full clean, including the browser and startup damage this software usually leaves behind.
One warning. If you have received a phone call, a pop-up or an email telling you your computer is infected and giving you a number to ring, that is the scam itself. No legitimate company knows your computer is infected. Hang up, and do not let anyone you did not contact first connect remotely to your machine.
5. It is choked with dust and thermally throttling
This one is genuinely under-appreciated, and in Brisbane it matters more than in cooler cities.
When a processor gets too hot it deliberately slows itself down to avoid damage. That is thermal throttling, and it is working as designed. The problem is that after a few years of dust accumulating in the heatsink and fan, a machine can spend most of its life throttled — running at a fraction of the speed you paid for, permanently.
How to tell: the fan is loud and constant, the case or the underside of the laptop is hot, and performance gets worse the longer the machine is on. A computer that is fine for ten minutes and then crawls is the textbook case.
The fix: a physical clean-out and, on older machines, fresh thermal paste between the processor and its heatsink. It is part of our computer cleaning and tune-up service. On a badly clogged laptop the difference is immediate and dramatic.
6. There genuinely is not enough memory
RAM is your computer's working space. When you run out, Windows starts using the drive as overflow, and the drive is thousands of times slower than RAM. That is the moment where everything stops at once for several seconds.
How to tell: open Task Manager, click Performance, then Memory. If you are sitting above 80 percent while doing ordinary things, that is your answer. In 2026, 8GB is the practical floor for Windows 11 and 16GB is where things stop being tight.
The fix: more RAM, where the machine allows it. Many modern thin laptops have memory soldered to the board and cannot be upgraded, which is worth knowing before you spend money on a diagnosis. Desktops almost always can be.
Before spending anything, though, check how many browser tabs you have open. Browsers are now the most memory-hungry software most people run, and thirty open tabs will exhaust 8GB on their own.
So which one is it?
In our workshop the rough order is: mechanical hard drive, then dust and heat, then startup clutter, then storage space, then malware, then memory. If your machine is more than four or five years old and still has a mechanical drive, start there — it is usually the whole answer.
What we would gently push back on is the instinct to replace the computer. A large share of the machines brought to us as "too slow, time for a new one" are perfectly good computers with one fixable bottleneck. Finding out costs a phone call.
Not sure which one applies to you?
Describe what it is doing and we will tell you what it is likely to be, before you spend anything. Most tune-ups are finished within the hour, and you are told before we go past it.
Written by the technicians at Afford IT, Indooroopilly. We service homes and small businesses across Greater Brisbane.