I would try booting a Linux Live CD, maybe DSL (Damn Small Linux) from a CD, and see if that boots error free. If it doesn't, try another Linux just to be sure (Ubuntu?). If neither of these boot, then it would suggest a hardware fault. If they do, it would suggest a fault with Windows. The fact that you can't get into Windows using safe mode is worrying, and to me would suggest a hardware fault.

I'm not sure what a PCI bus is or does, so I can't say if it's necessary or not!

Thomas