aha! yet another update on this case (yes i know i'm getting sick and tired of it also). Everything seemed to be fine (memtest and proc test all came back showing no errors) no bad HD sectors, and power and temp are fine (down to 26 degrees C idle and never over 38 when running anything at high settings).
Anyway last night i fired up RO changed all my gfx settings to highest or high (keep the AA to x4 and the filtering to x8...which never used to crash my machine). Anyway i load into a map then bang comp restarts. Funny thing is this only happens on RO any RO mods (and company of heros). The point is it only happens on Steam games and it doesn't happen on all of them. I'm completely stumped now. Maybe my ram or mobo is bust again any ideas are appreciated but i've run everything i can and nothing seems to be broken. Again i thought maybe my new gfx was bust but then why can i run Crysis at 40+ fps with everything on high but not RO...could it be that the malware on my system damaged RO, RO Mods and COH somehow? why only those games why not Portal or HL2?
As you can see i'm literally out of ideas short of buying all new mobo, ram, processor and a new OS, formatting my HD and starting over.
p.s. cleary its not just unreal engine games (coz of COH) but just to make sure i also have other UE2.0 engine games (i know RO is 2.5) and none of those crash...in fact nothing else causes my machine to crash other than those 3 games....