Hi, I've only recently had the chance to play around with my new build and I think it's on it's way out already. The spec is in my signature but I think the issue is with either the CPU, AMD Phenom II X4 955 BE or the mobo, MSI 790 GX-G65. 
I first noticed the issue yesterday evening when I tried to watch an episode of Family Guy, about three minutes in the PC just shut off, restarted and hung before POST with no display. So I switched it off, cleared the CMOS using the button on the MB and tried to boot it up. Again no POST or display so I checked all the connections, cables etc and couldn't see any issues so I left it after 20 minutes or so of swearing and moaning and went to bed.
I thought I'd give it another shot this morning, so I pressed the power button expecting the same issue as yesterday but no, everything loads up fine. I set the date and time in the BIOS and left everything else as Auto. After logging into Windows I used AMD Overdrive to see what temps the cores were running at, idling at 36 and maxed out at 54 whilst running the stability test - which passed without any problems. I then loaded up Empire Total War, as it's probably the most CPU taxing game I'm going to play anytime soon, which was running great until about and half in when the PC shut itself off again. Same process as last night, I was checking AMD Overdrive every 15 minutes or so and never once did the temp go over 44 - so I don't think it's a heat issue.
So I cleared the CMOS again, out of hope more than anything and it loaded fine, played another hour or so and bang it happened again...
Suffice to say the PC refuses to boot at all now, much like yesterday evening, I've disconnected all the cases fans, HDD's, floppy drive, DVD drive , tried it with a single DIMM, used the onboard VGA, disconnected and reconnected the PSU cables, prayed to Zeus, Yoda and Leonard Nimoy and still nothing. The CPU fan spins and that's about it... I can't even turn it off without disconnecting it at the mains - not even the onboard power and reset buttons have any effect on it and the power LED doesn't even flash.
Sorry for the long winded post, I am hoping someone will recognise the issue and point me in the right direction. I've got another couples of days in which to RMA the mobo and another couple of weeks for the processor.

I first noticed the issue yesterday evening when I tried to watch an episode of Family Guy, about three minutes in the PC just shut off, restarted and hung before POST with no display. So I switched it off, cleared the CMOS using the button on the MB and tried to boot it up. Again no POST or display so I checked all the connections, cables etc and couldn't see any issues so I left it after 20 minutes or so of swearing and moaning and went to bed.
I thought I'd give it another shot this morning, so I pressed the power button expecting the same issue as yesterday but no, everything loads up fine. I set the date and time in the BIOS and left everything else as Auto. After logging into Windows I used AMD Overdrive to see what temps the cores were running at, idling at 36 and maxed out at 54 whilst running the stability test - which passed without any problems. I then loaded up Empire Total War, as it's probably the most CPU taxing game I'm going to play anytime soon, which was running great until about and half in when the PC shut itself off again. Same process as last night, I was checking AMD Overdrive every 15 minutes or so and never once did the temp go over 44 - so I don't think it's a heat issue.
So I cleared the CMOS again, out of hope more than anything and it loaded fine, played another hour or so and bang it happened again...
Suffice to say the PC refuses to boot at all now, much like yesterday evening, I've disconnected all the cases fans, HDD's, floppy drive, DVD drive , tried it with a single DIMM, used the onboard VGA, disconnected and reconnected the PSU cables, prayed to Zeus, Yoda and Leonard Nimoy and still nothing. The CPU fan spins and that's about it... I can't even turn it off without disconnecting it at the mains - not even the onboard power and reset buttons have any effect on it and the power LED doesn't even flash.

Sorry for the long winded post, I am hoping someone will recognise the issue and point me in the right direction. I've got another couples of days in which to RMA the mobo and another couple of weeks for the processor.
