Once you've updated your anti-virus program and run the spyware remover you should find your computer starting to perform better.

But what if that hasn't fixed everything?

Where should you look next?

The next place to look is probably in the Windows Registry.

This is the dark, scary place where Windows stores all of your settings for your computer and the software you run.

Whilst it is possible to sort out the Registry by hand, most people don't do that as it can leave your computer unstable or even completely un-working.

Instead, it's best to use a computer error checker program that will safely inspect your computer's registry and then fix any problems it finds.

The software I recommend is Error Sweeper. It does everything that a regular Windows Registry cleaning program does and a lot more. Frankly, the less of this kind of software I have cluttering up my hard drive, the happier I am. So any program that reliably does several jobs at once is more than welcome.

The software will look at your currently installed programs and will also track down any registry entries that aren't necessary. If you've ever uninstalled a program, you've almost certainly used the "Uninstall" option on the start menu or, if you're more adventurous, the "Add or Remove programs" option in your computer's Control Panel.

Either way, the chances are that there are still bits of the program lurking around in the Windows Registry, slowing down your computer.

Error Sweeper will sort out these issues for you.

The other issues it will sort out include shortcuts that are no longer valid - these may not be slowing down your computer but they are certainly annoying when you click on them and wait for Windows to hunt around, trying to find a file that no longer exists or has been moved to somewhere else on your hard drive.

If you're experiencing errors when Windows starts up, Error Sweeper will also take care of those. After running the software, you should find a noticeable improvement in the time it takes your computer to boot up. Who knows, you may not even have time to brew a cup of coffee whilst Windows decides what to do when it's starting up.

Windows is often guilty of slowing down your computer.

One of ways it does this is how Windows stores the programs and other files on your hard drive. It is messy. Really messy - worse than a teenager's bedroom messy!

Fortunately, with todays fast hard drives this isn't too much of a problem, but you can sort it out by double clicking "My Computer". You'll then see a list of your hard drives. Select the one you use most often (likely the C drive) and right click your mouse on the link.

Towards the end of the menu that appears, you'll see an entry called Properties. Click this. Then click the tab called "Tools". Then click the "Defragment Now" button and then (finally) the "Defragment" button. Windows will go off and slowly defragment your hard drive. It's not the most efficient program in the world but it's free with XP and Vista and will get rid of most problems.

There are more specialist tools available to do a more thorough defragmentation but, quite honestly, you're unlikely to need them with a modern machine.

Another way to speed up your machine is to treat it to more memory. Modern programs use lots of memory. If Windows hasn't got enough memory installed, it will use your hard drive as the next best thing. This is a slow process and will impact your machine's performance.

To find out how much memory (RAM) your computer has, right click "My Computer" and select Properties from the menu that appears.

The screen that appears should tell you the version of Windows that you are running and who it is registered to. Further down, it will say the processor your machine has and how much RAM you've got.

If you're running XP or Vista, this should be around 2GB (likely the figure will be slightly different because of the way computers treat these figures - my machine has 2Gb of RAM but Windows only reports 1.96GB, which is fine).

If you've got less RAM than this, it's time to upgrade your memory. You can do this yourself or your local computer shop can help you. Either way, you'll almost certainly notice an increase in speed as Windows doesn't have to spend as much time storing information on your hard drive.

While you've got that Window open, click on the tab called Advanced.

One of the options you'll see is called Performance. Click the Performance settings button. Unless you've opened this tab before, the chances are that your computer settings will say "Let Windows choose". Click the "Adjust for best performance" option instead - you'll lose a few of the nicer display options but you'll appreciate the increase in speed this gives you until your new computer memory arrives.