During the last few days, I’ve seen the performance of my home Windows XP machine slowly decline - to the point of a serious slow down. Up until I fixed the problem, (which I’ll now describe), the PC was constantly writing to the hard disk – it was constantly chugging, clicking and whirring.

If you have this problem, there are a few things you could try. I’ve left the big-boy “fix-all” solution to the end:

• Have you got spyware? Use quality virus checking software, or specific Spyware catching software. (I have McAfee Virus Scan and also System Mechanic Professional from iolo)
• Have you got many restore points, have you got the System Restore option switched on? If so, try to disable it. The restore points take up huge amounts of disk space and can also slow your machine right down. To do this right-click on My Computer, click on the System Restore tab and click the Turn Off System Restore option. Alternatively, like me, if you have your drive partitioned (split like C: and D: and so on) you might want to keep C: enabled as that’s where the important meaty system stuff is kept
• Have you got Windows Indexing switched on? WI indexes content and properties of files on local and remote computers and provides rapid access to these files. If you have got it on, try to disable it by going to your Windows Service and stopping it, or even disabling it. The quickest way to do this is to go to Start > Run > services.msc > Indexing Service > Properties > and switch the service status to Disabled
• Have you got some dodgy or weird process running that’s all consuming? Microsoft have a great freebie process explorer checker. You can download it here. They also have some great general PC health care tools on the Windows SysInternals site 
• The catch-all that seemed to cure everything was that, unknown to me, there is a registry setting that makes your Windows XP PC perform a disk defragmentation when idle. If you don’t have much free space left on your hard-disk then the defrag tends to work overtime. The easiest way to disable this is to download the Windows Powertool TweakUI. Once this is installed, go to the General section and unclick Optimize hard disk when idle

I now have no problems at all, apart from I need to remember to defrag manually from time to time.