I have a laptop running Windows XP that is around 3 years old. It has recently started running really slowly and when I had similar problems with the desktop, I'd remove what I need from it, and reinstall the Operating System. However, I didn't get an XP backup disk with the laptop and I want to reset it to the default factory settings - can someone please tell me how to do this?

(I realise this is a drastic step but I've got an awful habit of downloading loads of problems that I hardly ever use and the Remove programs wizard doesn't seem to have all the programs I've installed over the years! Any other methods to free up resources would be appreciated. It's now got around 2GB free memory as I deleted some old files but it hasn't seemed to help so I figure a factory reset seems the best option. P,S Sorry for rambling! )