I have been researching for five hours now, so I'll feel stupid if I missed something.
I have WinXP Pro. In the past few weeks it has been spontaneoulsy rebooting for no apparent reason. I downloaded RAM and HDD testing software (from research right here, thank you!) and they seem fine.
Now it will boot to the command promp,safe mode but it takes like 15 minutes.
Weird thing is that I put in the cloned as sole master, identical HDD from about 3 weeks ago and it gives me the error "Boot error: 0-00, select partition to boot, 0-3". I tried "0" since that should be the boot partition and the screen goes black and never boots up. I can't get any farther and this is the clone drive that I clone and then unplug totally for emergencies like this.
The old primary drive that crashed won't even let me finish loading WinXP pro from the CD to get to a recovery console. It crashes BSOD about 3 min into copying over files.
I'm lost for now. Any ideas?