Similar to Zorch's predicament, I've a friend who's laptop is broken, probably due to viruses. It's at the stage where windows simply does not start up. I was going to stick some linux boot disk I have laying around in so that he can pull important stuff off of the hard drive (assuming the hard drive is still intact), but I've no clue how to go about repairing the operating system itself. I assume something involving booting using the setup disk would be a possible solution, but I don't know if he's even got that on hand. So, any suggestions?
EDIT: Oh, for clarification's sake, it'll get to the point where he can select to boot to normal mode / safe mode / whatever, but all of the options just result in an instant reboot.