I had a similar symptom when I transferred my XP partition to a new Intel
system I built. The new intel also had a SATA raid support, but
unfortunately the driver for the old SATA raid did not work for the new SATA
raid. I managed to forklift the driver into it by working with a parallel
install.
After selecting Previous Windows from the Vista boot loader, hit F8 quickly.
You should then get the boot.ini prompt with the option to boot into safe
mode and the like. If you get here, you know that you have gotten as far as
loading NTLoader. First try safe mode. If you can get in from safe mode,
you might be able to look at your event log to find out what failed. If it
won't boot in safe mode, most likely your storage media drivers is hosed.
Perhaps upgraded to an incompatible version. Since it worked before, you
could try Last Known Good. You might even try that before trying safe mode.
Your boot.ini entries may be bad too. Double check them from Vista.
