I just had a look round another place & chanced on a thread with a guy who got the same bsod/stop error messages as you.
After exhaustive testing, removing coponents/software/rebuilding, he narrowed it down to the cpu or the motheboard. Swapped the cpu & the system was fine so deduced it was either the cpu or the cpu/mobo interface.
Either way, a few quid to spend to right things it would seem.
