What you need to establish is whether you have a Hardware
or Software problem ?
First of all, after what amount of time does the pc turn
itself off, has your computer got any other symptons
like "Slowing down" "freezing-acompanied by BSODs " - it
may be that the sys' is overheating-- what u many want to
do is boot up the pc & enter the sys' BIOS setup & leave
it there for a few hours & see what it does --- there may
be a 101 reasons why its doing this...if its Software..you
may want to boot up the sys' into Safe mode & leave it
there..all these suggestions along with Roger's suggestion
(By the way roger you once helped me sort out some EFS
problems i was having --- your help was worth GOLD ..thank
once again) .... will help you out -- so keep us update
regards,
martie.