Two week old Aurora keeps randomly locking up and or, rebooting

I received my Aurora a couple of weeks ago, and since then, I have been experiencing random freezing in windows, or reboots while gaming.  I called Alienware tech support, they had me run the diags and such, and determined that it was a faulty 5770 video card.  They sent a replacement card, and while the crashes are not as often, they used to be 6-10 times a day, I still have random crashes daily.

I ran memtest 86x for over 24 hours two times, and my 12 gigs of RAM passed both times, I run system diags and it says that everything seems to running normally.  Prime95 never gets my CPU over 71c and I've run GPU stress tests on the card and the card gets to about 78c but the system doesnt shut down.  I'm running out of patience, I get critical errors about the kernal or something in the event log, and sometimes when I just do something as simple as shut down the PC, it freezes on the logging out screen.  I have updated all of my drivers, to no avail.  Any help, or suggestions with what to do next would be greatly appreciated.   My i7 is running stock, the memory is running stock, and so is the video card.  I havent overclocked anything.