If the hard drive has failed -completely- then your Vista OS will certainly not install!
Are you sure your hard drive is dead?
Is there an imminent failure message?
Is SATA enabled in the f10 BIOS menu?
Was she installing drivers,or any thing else,before the hard drive died?
You could download "partition magic.iso" free and re-write the master boot record
to the first sector of the drive. This could,potentially,solve the problem!
Otherwise,if you send me an email address. I have a small program that i would be willing to share. Which most likely would fix
your hard drive and restore your system to normal,assuming the drive has not completely failed!