A link that may or may not help:
Windows 7 Black Screen Of Death Fix
You may or may not get help from Microsoft on this one:
Virus and Security Solution Center
As an afterthought, do you have access to a Windows 7 DVD (not a recovery disk or repair disk) that you could beg, steal or borrow to boot from?
Lastly, there is a possibility there's a major problem with the hard drive.