Guide · a slow computer
Why is my computer so slow, and how to speed it up.
Here is the reassuring part first. A slow computer is the single most common complaint we hear, and it almost never means the computer is broken or has a virus. Far more often it is just carrying too much, the way a car with a full boot climbs a hill more slowly. A good clear-out, and sometimes a small upgrade, brings most of the speed back.
Last updated 4 July 2026 · by Alien IT Solutions
Slow does not mean broken
The fear, quite naturally, is that a slow computer is a dying computer, or that something nasty has got into it. In truth that is rarely the case. Computers slow down gradually over the years for very ordinary reasons, and most of them you can put right yourself in an afternoon.
So before you worry, or spend a cent, it helps to know what actually causes the slowness. Once you can see the reason, the fix is usually simple.
The real reasons a computer slows down
It is almost always one or two of these, and none of them mean the machine is failing.
Too much loading at startup
Over the years, programs quietly set themselves to open the moment you switch on. Each one is a little more weight the computer has to lift before it is ready. This is one of the most common causes, and one of the easiest to fix.
A nearly full drive
Your files live on a drive, like a filing cabinet. When it gets close to full, the computer has no room to work in and everything drags. Clearing some space often brings a noticeable lift. The same thing happens on a phone, so if yours keeps saying it is out of room, here is how to free up storage on your phone.
Too many browser tabs
Each open tab in your web browser is a small program running. Twenty tabs left open all week can slow the whole machine. Closing the ones you have finished with often helps straight away.
An old spinning hard drive
Older computers store files on a spinning disk that is slow by today's standards. A modern SSD replaces it and is many times faster. This is a common reason an older machine feels sluggish no matter how much you tidy.
Updates waiting to install
When the computer is part-way through downloading or installing updates, it slows right down until they finish. Often the fix is simply to let the updates complete and then restart.
Too little memory
Memory, sometimes called RAM, is the workspace the computer uses while it is running. If a machine has very little, it struggles when you have several things open at once. More memory can be added to many computers.
And yes, once in a while it is unwanted software, sometimes loosely called malware, quietly running in the background. It is far less common than people fear, and it is the last thing to suspect, not the first.
The safe fixes anyone can do
Work through these in order. Each one is safe, costs nothing, and none of them can harm your computer.
Restart it properly
Not just closing the lid. Choose Restart from the Apple menu on a Mac, or from the Start menu on Windows, and let it fully switch off and come back on. This alone clears out a great deal and fixes a surprising number of slowdowns. It is always the first thing to try.
Close what you are not using
Shut the programs and browser tabs you have finished with, rather than leaving everything open. On a Mac a black dot under an icon in the dock means the program is still running. Closing them frees up the workspace the computer needs.
Empty the bin
Deleting a file only moves it to the Bin, where it still takes up room. Empty it to actually free the space. On a Mac, hold the Trash icon in the dock and choose Empty Bin. On Windows, right-click the Recycle Bin on the desktop and choose Empty.
Uninstall what you never use
Old programs you have not touched in years take up space and sometimes run in the background. On a Mac, open the Applications folder and drag ones you are sure about to the Bin. On Windows, open Settings, then Apps, and use Uninstall. If you are unsure what something is, leave it, or ask.
Turn off unnecessary startup programs
This tackles the big one. On a Mac, open System Settings, then General, then Login Items, and remove things you do not need to open automatically. On Windows, press Ctrl, Shift and Escape together to open Task Manager, click the Startup tab, and switch off items you recognise as unnecessary. Leave anything you are not sure about.
Check for updates and let them finish
On a Mac, open System Settings, then General, then Software Update. On Windows, open Settings, then Windows Update. Install what is waiting, then restart. Up-to-date software runs better and more safely.
Clear the browser cache
Your web browser stores a pile of temporary files that can build up. In Chrome, Edge, Safari or Firefox, look in the settings for an option worded like Clear browsing data or Clear history, and clear the cached files. Your saved passwords and bookmarks stay safe.
The difference between a Mac and a Windows computer
The idea is the same, the buttons are in slightly different places.
Everything above works on both kinds of computer, though the two look quite different. On an Apple Mac, most settings live under the Apple menu in the top left corner, and in System Settings. On a Windows computer, they live under the Start menu in the bottom left corner, and in Settings. The words differ a little too. The Mac calls it the Bin, Windows the Recycle Bin, but both do the same job.
You do not need to remember which is which. If you know what you are trying to do, restart, empty the bin, turn off startup programs, you can usually find the matching button on either machine. And if the wording on your screen does not quite match this page, that is normal, because both makers change the words from time to time.
When it is worth paying for help or an upgrade
Sometimes a small spend gives you years more out of the machine you have.
If you have worked through the safe fixes and the computer is still slow, that does not mean it is time for a new one. Two upgrades in particular can make an older machine feel brand new for a fraction of the price of replacing it. The first is fitting an SSD, the modern fast drive, in place of an old spinning one. It is the single biggest improvement for the money, and on many computers it is a straightforward job. The second is adding more memory, which helps a machine that struggles with several things open at once.
Whether either is worth doing depends on the age of the computer. As a rough guide, if the machine is only a few years old, an upgrade is usually well worth it. If it is very old, or the repair starts to approach the cost of a new one, replacing it may be the wiser choice. The honest answer is different for every computer, and it is worth having someone look at yours and tell you plainly which way it falls before you spend anything.
A word on the scary pop-ups
The message that says your computer is infected is almost always the con, not the cure.
While we are on the subject of speed, a warning. If a website or a pop-up suddenly tells you your computer is infected, running slow, or full of errors, and urges you to download a program or ring a phone number to fix it, do not do it. That message is the problem, not the solution. It is a common trick designed to frighten you into installing something harmful or handing over money.
The genuine tools to speed up your computer are the ones already built in, the very steps on this page, and they never cost a thing or arrive as an urgent warning. If one of these messages has you worried, the safe move is to close it, not click it, and to ask someone you trust rather than the number on the screen.
None of this needs to be done alone. If the steps feel fiddly, or you would simply like someone to sit with you and get the machine running sweetly again, we are glad to help in plain words and at your pace. If you are not sure where to begin, our guide on where to start with tech help is a gentle place to open, and there is a fuller seniors tech help guide covering the wider basics too.
Who wrote this
Seniors IT is the patient, in-home help service of Alien IT Solutions, an Australian technology company with more than 18 years of experience. It is the same trusted team, with the time and patience the job needs, and the same people families rely on for business IT and home technology.
Questions people ask
Does a slow computer mean I have a virus?
Usually not. A virus is far down the list of reasons a computer runs slowly. Nine times out of ten it is something ordinary, like too many programs opening at startup, a nearly full drive, or updates waiting to install. Work through the safe fixes first. If the computer is also showing pop-ups you did not ask for, or a warning that demands you ring a number, that is worth having someone look at, but slowness on its own is almost never a virus.
Will deleting my photos speed up the computer?
Only if the drive is almost completely full. A very full drive does slow a computer down, and clearing space helps. But deleting a few photos rarely makes a real difference, and you should never delete photos you have not backed up first. If space is the problem, emptying the bin and removing large programs you never use will do far more than losing your memories.
Is it worth fixing, or should I just buy a new one?
It depends on the age of the machine and the cost of the fix. If the computer is only a few years old, a small upgrade like a solid state drive or more memory can make it feel brand new for a fraction of the price of a replacement. If it is very old, or the repair costs are getting close to the price of a new one, replacing it may make more sense. It is worth having someone honest tell you which it is before you spend anything.
What is an SSD, and will it help?
An SSD, or solid state drive, is the modern replacement for the old spinning hard drive that stores your files. It has no moving parts and is many times faster, so the computer starts up and opens programs far more quickly. If your computer still has an old spinning drive, fitting an SSD is the single biggest speed improvement you can make, and it is often surprisingly affordable. It is the first upgrade worth asking about.
Do I need to buy a cleaning or speed-up program?
No, and it is best not to. The safe fixes on this page are all built into your computer already and cost nothing. Many of the cleaner and speed-up programs advertised online do little good, and some make things worse or are simply a way to charge you money. If a website or pop-up tells you your computer is infected and you must download something to fix it, that is a scam. Stick with the tools your computer already has.
Why does my computer get slower over time?
It is normal. Over the years you install programs, the drive fills up, more things quietly load at startup, and websites and updates ask more of the machine than they used to. None of that is a fault, it is just the computer carrying more than it did when it was new. A good clear-out and, if needed, a small upgrade will usually bring back most of the speed it had at the start.
Patient help, in plain words.
Want a hand getting your computer running sweetly again? Book a friendly visit for yourself or an older relative. No jargon, no lock-in, at your pace.