All of a sudden Vista is not booting up past the logo screen (with the green animated progress bar). Actually, it goes into blank screen mode after 1-2 minutes and nothing happens ever after that.

Worst yet, even the Vista Ultimate CD (which I used originally to install, twice before) is NOT loading past the same screen (logo)! it first goes through the 'loading windows files...' then boots to the logo screen and nothing happens for several minutes!

I also tried booting in safe mode, it goes through the scrolling of loading files and always gets stuck on crcdisk.sys file