Update
I was having a look through the internet in case I'm missing something on my OC (it has been running stable for quite a long time but one never know...) I went to the BIOS for finer adjustment, and tried the AIDA64 test (it's the only thing I have installed after the fresh Win installation). Surprisingly it reported overheating very soon and consistently. Droped the voltage but same result.... So, open the case, and I couldn't believe it, the fins of the CPU radiator were compleately locked with a thick layer of dust, right between the fan and the fins... and not long I clean it up though... but we have moved house and country, so the new place may accumulate more dust than the old one...
Good clean up and problems gone emediately: Aida64 kept the test runing for a while with the normal OC without errors, the simulator didn't crashed as before... all looked a lot better... but this morning, running the sim, the computer just restarted, just like that no BSOD at all, in a split of a second, black-restart screen. The PC went back on, I run Aida64 test and emediately a hardware error came up. I have attached the zip again in the hope they can reveal something (DV it was suposed to be running as well).
I have also attached the Aiday pic
Cheers