Just recently had to fix a laptop that I thought was a goner. It was getting a BSOD. Usually I fix this with a chkdsk scan on the hard drive. It had a number of corrupted files. After the scan the computer would not boot up past the BIOS logo.
This to me suggested an hardware issue, at first. I decided to scan the memory using -http://www.memtest.org/ . It came out clean. Using Vista's built in repair utilities did nothing either. http://www.bleepingcomputer.com/tutorials/tutorial148.html
The owner had a lot of pictures on the computer she wanted saved, and told me if I could salvage them that would be good enough. Even though I suspected a hardware issue at this point I decided to run a anti-virus boot cd http://www.avg.com/us-en/avg-rescue-cd
I booted of the CD, ran an update first, and just let the scanner do it's job. Along with the corrupted files, this was a seriously infected system. After I tried to boot up again but didn't get any further.
I decided then to concentrate on trying to recover the pictures. I downloaded a live cd of the internet to at least try to save the pictures onto my flashdrive. I came across one called Vista Live CD. They are usually created directly from the Operating System files, so it seemed like the perfect choice.
All legalities aside, I downloaded it, burned it of and used it to access the laptop. Unfortunately, it wasn't all English which made the task of copying the pictures to my drive a lot harder to do because an error/warning message keep popping up and I had no idea what it was trying to tell me.
It became so frustrating I gave it up and just started scanning the CD for something else that might help and I noticed a utility to Repair Vista. I figured I had nothing to lose at this point and gave it a shot. I let it run and when it finished it said there where a number of startup errors and fixed them. I took out the CD and rebooted the system again.
Amazingly, this time I got to the log-in screen. I know his person doesn't have a password set up because I had to erase it before when she forgot it. I don't think she set it up again. And this log-in screen seemed odly different. There was no picture, just an empty frame with a empty space under for a username and a empty space for a password.
So I had to use another boot cd that I used before to erase the password to get logged in. Finally, I Was In. Not surprisingly, the Anti-Virus (Avast) was disabled actually I thought it was corrupted. When I tried to get it restarted, I couldn't. I tried an update and that cleared it out. Got everything working again. Then I updated and ran Malwarebytes. Did a full scan. It found a few more things that I deleted.
One more thing to do. I decided to burn of her pictures. 5GB on two DVDs.
My conclusion was that a serious viral/malware infection corrupted the hard drive making it almost impossible to recover.