Worrying noises

My computer is making stranges noises. Worryingly it sounds like it might be the hard drive. Fortunately I do back up anything of importance, so it merely pain in the arse time if something is about to go wrong rather than total catastrophe.

This PC has been quite a resilient beast, although if think about it I think it's on it's second hard drive already. Had it for ooh 4 years or more now I think, something like that. It's survived a cat pissing in the CD tray when it was sitting open, not to mention being pissed on a few other times on the outer casing again by the smae fucking cat not by myself. Think I replaced it myself if I recall, it's never been taken to a shop. Ah well not to worry. So long as it's that simple it'll be no biggie.