Windows not booting on Toshiba Laptop

[redrage]

I just helped my gf clean up her laptop, deleted a few unused files, installed firefox, cleared the cache, and installed AVG 8.0. It zips around a lot faster on the internet now but she just tryed to use her Zune program and it froze, She went to reboot and after the bios runs and it goes to start up windows the screen becomes black and nothing happens. Anyone know what could be causing this and how i can fix it?

 

[frozenlead]

This really doesn't belong in this section of the forum, it isn't much of a laptop question.

However, I suggest you repair windows. You may have damaged some OS files, perhaps.