A little Help please

Hey Now,
My brother in law has a "boot sector failure" and has tried a few things already. Has anybody recently come across anything like this recently on their machine? The kapursky (SP?) thing didn't work at all. Here's the problem: he has an hp tower that came with vista and then they sent him the windows 7 upgrade disk. So he doesn't have an original vista disk. (although he does have the sn from the stickers on the side and does still have the upgrade disk. )
Any help is most appreciated- thanx!
Zero.

call HP they should be able to send hime a replacement disk