My brother has Windows Vista Ultimate installed on his computer. He's a little younger than me and I've always told him to not shut down your computer manually by pressing the power button on the computer. Still, no matter what I say, he does it anyways. I think this problem is a cause of that and now on Mid-Winter Break he will be without a computer. He told me he had shut it off (by manually pressing the power button) and powered it up again. The screen went black. I took a look for myself and it had given the option to select the operating system (Windows Vista) and/or Memory Diagnositics Test. I first selected Windows Vista, from there it gave me options like Start Normally, Safe Mode, Safe Mode with network, etc. I tried every single one of those and nothing, it lead me to another screen asking me to insert my Windows Vista Installation Disc which I do not currently have with me. I was hoping there was a another way to fix it other than that, but if not I guess I will have to find my disc. Anyways, from there I exited that screen and did the Memory Diagnostics Test, it completed and everything but it just lead me back to the screen with Safe Mode options, etc. It's error code: 0xC000014c and says C:\Windows\system32\config\system. 'Registry file is missing or corrupt.' So if anyone could help, I'd be greatly appreciated. Thanks in advance!

Boot from the Vista DVD and launch Startup Repair: http://www.bleepingcomputer.com/tutorials/tutorial148.html

But what happens if I don't have the CD, I believe my dad sold it.