Please see my previous question for the history.
I have a replacement processor in the PC now and I have reset the CMOS, formatted the hard drive and reinstalled windows. However the PC keeps on turning itself off without warning.
The CPU clearly was dead, because previously the PC wasn't booting at all. With the alternative CPU the machine is 'working' however it will just randomly turn itself off when you're in the middle of something.
After it has turned itself off the light on the front blinks on and off every second and it won't let you start the PC up again until you have removed the power cable for long enough to make the light stop blinking (about 5 seconds).
It must be a hardware fault as it's a brand new installation of windows. The CPU was working fine for my friend, so I guess it can only be the mobo / memory / HDD.
Has anyone got any suggestions before I take it down to the car park and drive my car over it repeatedly?