Hopefully, problem solved!
I kept getting the ''Error Message: STOP 0x000000EA
(http://support.microsoft.com/?kbid=293078)' error whether the PC was
sat idle or I was using it. Checking my logs, my best was 12 reboots
in one day. Not bad I think you'd agree!
After much trawling I stumbled across a solution that recommended
entering the nVidia Control Panel and disabling both the
'Multi-display/mixed-GPU acceleration' and the 'Threaded Optimisation'.
I did as yet no reboots, even after several hours of use with
Dreamweaver, iTunes and Photoshop all open at once. I even had a quick
game of Hold 'em and no BSOD.