My Vista computer is (without any prior problems) shutting down at the progress screen. Computer will post, get to the progress screen and after a few seconds the bar stops and the system shuts down. It will not boot in safe mode either. It will boot from the vista disk but when I run the system repair it also shuts down. I tried a different drive and doing a clean install but it won?t finish and shuts down again. I have not installed any new hardware [vista hardware]mod.info/category/vistamods/>[hardware mods] or software. The one thing I can do is boot from a Knoppix CD, and it runs fine. I can see the vista drive and all its contents from Knoppix. I?m pretty stumped on this one. Any thoughts would be appreciated.

This is my configuration;

Vista 64 Ultimate
Intel Core 2 Duo E6300
Intel DG965WH Motherboard
1GB Kingston PC2 5300
PNY Nvidia GeForce 7300 GT
Antec 500W Power Supply
LiteOn SATA DVD
Seagate 320GB SATA