And just when you think everything is fine again, it stops working yet again! :p
I've now swapped out my 3d cards (old x1600xt and new hd2900xt), but despite not being able to fit my hd2900xt in the second slot because of a new hard disk ... I have found out none of the two 3D cards actually start spinning their fans now.
Meaning a dangerously hot x1600xt 3d card. Also meaning, my 3D card is not broken. Which makes sense as it ran Crysis a few days back after the issue started for more than 3 hours without ever failing.
Seems my mainboard, something I did not hope for, is the culprit after all! :S
Cheers