He must have said his specs wrong. AMD CPUs are not even remotely compatable with Intel boards. They don't physically fit in the socket.
Elf, do you get any sort of logdump when you crash? Posting that in a tech forum (this one might not be quite the right option, though go ahead and try if you like) is a great first step. If you AREN'T getting a logdump...
Otherwise, I'd have to guess it's your PSU as well. They are usually the first thing to fail on a computer, and that model in particular has a number of complaints on Newegg about shutting down under load. It's possible yours wasn't initially defective, but either has been gradually dying or spontaneously died right around the update you mentioned. If you know a techie with a multimeter, you can have them test it for you. Don't test it yourself unless you know what you are doing, though, as they are VERY dangerous to mess around with.