My grandads pc just broke so he gave it to me. I slaved the harddrive to get the info off and thats fine. But it wont boot up. It turns on, powers up, gets to the XP loading screen and turns off. There is a clicking noise and it goes off. I think it could be the pcu or ram but i have no experence. What do you think? Are there any self diagnosis websites ormtroubleshooting guides for future? Thanks