A friend of mine brought me her busted HP/Vista laptop. It won't boot and the system repair function can't fix the problem. She just wants her data rescued. So I figured I'd try booting a live Ubuntu (Linux) CD and see if I can mount the Windows file system. Meanwhile, she's searching for the system disks (with a low probability of success). Works just fine. So we can copy the data to some other system.
While I'm cleaning up, I poke around in the Windows top directory and find a huge file named hiberfil.sys. Its the Windows hibernation file. According to support forums, its OK to delete. Windows will just be forced to do a cold boot up. So I delete it and the system starts (in Windows) just fine. My guess: hiberfil.sys was corrupt.
Now, why the hell doesn't the Windows system repair utility start off by blowing away this (and any other saved state files) before just throwing up its hands and giving up?