Thanks looooads guys, Brando your right! Sorry I was a little drunk. Anyway it's still not working, I followed the brilliant advice you guys posted but to no avail. However you've given me some future tips I'll bear in mind. The good news is, I turned up at a local IT office on the way back from town. They usually repair buisness computers, but I think they felt sorry for me.

So for 45 quid which IMO is a bargain, they'll go through everything and diagnose exactly what the problem is. Which is great, I'm much happier doing that than ordering the parts in on a credit card and returning the ones I dont need. (brilliant idea btw)
I was contemplating breaking into my house and stealing my pc at one point.