If your installation of Windows XP has been there for a while - say 6 months or more - without you doing any housekeeping on the hard drive, then it may begin to get a little sluggish. I'm not talking about the problems caused by malware.

Computer hard drives need cleaning every now and then. That doesn't mean you take it out and put it in a bucket of soap and water! No, we're talking about getting rid of the junk that just seems to clutter up the drive.

The first tip involves spending no money at all, but uses a neat command to clean out temporary files that seem to grow in Windows like weeds in a garden.

If you know how, boot your computer in Safe Mode. Normally you do that by pressing several times the key marked F8 on your keyboard. You can safely ignore lots of beeps if they occur. If you've timed it right, a menu will appear. Click on the item near the top of the menu - Safe Mode and press .

After quite a lot of stuff flowing down the screen, the computer will boot into Safe Mode. It will tell you when it gets to Safe Mode. Just be aware that booting into Safe Mode is not the quickest activity in the world.

Anyway, when all is done and your dear old computer is sitting there, just click on the "Start" icon. Up pops the Start Menu and you will see over on the right-hand side "Search". Click on that and window will open with several options on the left-hand side. Just above that pesky dog.

Click on "All Files and Folders". On the left-hand side you will see a change occur and two empty boxes. You are going to type something into the box labeled "All or part of the file name".

Click in that box and type the following - carefully:

.tmp,.chk,.

No spaces and check when it's a comma or a period (full stop). Do not, repeat not, leave out the character (the tilde). If you do, you will need your hard drive backup!

Now, find the "Look in:" box and make sure only Drive C: is selected. Next, scroll down this left=hand window until you can see "More Advanced Options".

When you do, click on the words "More Advanced Options" and in the list that appears, tick "Search hidden files and folders". Then click on the "Search" button - well, rectangular box, actually.

Windows will now start searching for junk. It can take a good long time if there's a lot of stuff on your drive and it hasn't been cleaned for a while. I have waited many times for over 2,500 junk files to be found.

When this has finally finished, you will have a list of files (maybe a very long list) in the right-hand pane of the search window.

Select the top file with a single, left click. Then type CTRL-A (select all) and press delete. All of these files can be safely deleted.

It can take a while for files to disappear, especially if there are a lot. Be patient. They all end up in the recycle bin where you can really get rid of them.

Note that the .tmp,.chk,. instructions can be used in earlier versions of Windows - right back to Windows 95. Some of the other options won't be available.