Thanks for the reply. I noticed it indicates error messages everytime it crashes into blue screen.
These 2 are the notorious ones. I ran memory test and it seems fine. I unticked the non-microsoft drivers for start up and same error. However, I can make it work on Safe mode. IMO, possibly not the PSU. but you people are the experts so let me know.
Just to add: I updated all drivers thru Win 7 update, my rig seems to be working fine for hours now. Could it be that simple??? I was updating it like this before i re-installed the OS but it was crashing still...
If it happens again, I'll try the list by Panicmaster85 and update the thread. TIA