The reason for my pc freezing is that it's just generally falling apart. It hasn't been defragged in since it was built two years ago, the HD is 4+ years old and is nearly full and everything is going to hell generally. But don't worry, once my GCSE's are over i'm buying a new HD and taking a weekend off to completely rebuild my computer. Fresh installation of xp on the new HD, wipe xp off the old HD and use it to run programs off (thus removing the need to spend days reinstalling everything).

Good as new.