It seems that I am not having a good day with computers! Firstly, it now appears that my BIOS update I applied two days ago to fix this mysterious powering off issue has not fixed the problem at all as it has powered itself off twice tonight! Then I tried to rebuild my desktop as a server only to find that the hard disk has decided to pack up. In addition to that, my laptop seems to crash periodically when a monitor is attached. Not good.