vkarthik 0 Newbie Poster

I've been having this dumb question on my mind for long.

Suppose I make a copy of c:\Windows folder to an external store... At some point, let's say my OS doesn't boot due to corrupted system files (for now, forget MBR corruption and hard disk failure)... if I boot into Windows PE or a similar OS through an external drive and copy my Windows folder back to C: and reboot, will my system be back to normal?

I know that there is tons of tools to do a complete PC backup, including the jazzy new Vista Ultimate's backup suite. But put aside all that for now and tell me the simplest steps that one can take, to restore the OS files.

In particular, apart from hardware failure, what other failures can occur that prevents a disk from booting? Assume that I don't have dual boot and I use Vista... during a system failure, if I can manage running "bootrec.exe /fixmbr", "bootrec.exe /fixboot" and I use xcopy or imagex to restore the complete C:\Windows, will my OS be restored?

I trust this forum more than any other tech forum on the net, so wanted to pick your brains.

Thanks
Karthik