Vista freezing randomly at startup

"This could be a hardware problem. How long do you wait to see if the freeze clears itself?

The unexpected shutdown error after reboot implies that the OS is still running to some extent. From a hardware professional standpoint, if the CPU is still running it is a ""soft lock"" and can be much more easily debugged. A ""hard lock,"" where the CPU is completely out in the weeds, is more difficult to debug. Any lock up is not easy to debug in a home environment, though. The process of elimination is a pretty effective method to use. Since other OS's work, that rules out a lot of potential issues.

Have you tried different variations of booting Windows?

Safe Mode? Helps rule out drivers.
A clean install of Vista? Helps rule out bad OS image.
Boot with minimum hardware configuration and add HW one piece at a time?"

"It doesn't sound like a hardware issue to me.

I would suggest running CCleaner (www.ccleaner.com) to not only clean the garbage files on your Windows partition, but to also run CCleaners built-in Registry cleaner. I have a PC repair business and this program has never failed to impress me, and I install it on all Windows-based computers that I repair.

Additionally, run a couple spyware programs, such as MalwareBytes and Spybot. You may have some malware, spyware, etc., messing with your Windows side.

Finally, run a good anti-virus program with updated definition files.

I think the above should eliminate any issues you describe above. Good luck."