Okay, who's good at fixing laptops that won't boot?

...see, I have this laptop running WinXP Pro. Every time I try and turn the sucker on, it boots up for a bit, then gives me a dreaded blue screen with a wonderfully useless error message:

Unmountable boot volume

..yeah, great. So anyway, after reading lots of boring information about it, apparently I need to get a DOS prompt up so I can try and repair. Problem....no XP CD. I'm pretty sure my .ini file is okay, as I checked it out via a Linux disk and it seems fine. From what I've read, this means it's my master boot record that's the problem.

I've also seen a bunch of other stuff mentioning how you can fix it with floppy disks, but of course the laptop doesn't have a floppy drive. As a final kick in the pants, I did manage to find a single ISO for WinXP but for some reason, the stupid machine won't accept the CD as bootable. What I really need (I think) is some kind of master boot record fixing supertool that I can preferably run with no hassle from a USB key because I'm not 100% sure about the sanity of the CD drive at the moment. As a final note, I'm not bothered about the data on the disk as I can easily recover that via the Linux CD, or back it up if your suggestion is potentially explosion-inducing.

Help me solve this problem and I'll marry your sister.