I am just going through the experience of recovering a crashed computer (which I uses for work). It was cranky and crying for attention quite some time now. Last week, I was trying to install virtual machine (Sun’s Virtual box) and playing around virtual network card configuration. And in the same time, I got my Win XP service pack upgraded to SP3. I don’t know if that was due to driver mismatch or something. I was getting Blue Screen of death (BSOD) while starting Windows (both normal mode as well as Safe mode).
When tried to rescue with BartPE boot CD, I was not able to see C drive and in the same time, I could see other logical partitions. So only option is to reinstall the operating system.