So quick wrd of advice, always backup your computer regardless what the OS is. And if you are faced with the dreaded Vista bootloop and don't have backups; I suggest:
1- Use another computer to download and burn a Live Linux CD (try Ubuntu).
2- Boot the Live Linux Cd and attach an extrrnal hard drive, flash drive, etc.
3- Mount the computer's C: drive and backup all known user made file (pictures, music, video, etc.).
4- Proceed with a reload of the operating system (if you have tried everything else).
In attempt to avoid using the factory restore disks (mostly due to not having them available), I have essentially wasted several evenings worth of work this week for what could have been an hour and a half reinstall. Just saying!