Brand new PC, monitor shutting off randomly

[diiPex]

Hello Linustechtips forums, normally when I have a problem that Google cannot answer for me I give up, but I figured this time it might be worth another shot.  

 

So, I just built a brand new PC for my brother, and everything has been working fine... for the most part.  Randomly, I'd say every 3-6 hours, the monitor will shut off giving the standard no signal error as if the computer was powered down, but here's the thing; the computer's still running, you can still talk through skype and everything (imagine using a fully functional computer with the monitor unplugged). The problem isn't quite as random as once every 3-6 hours however, when it happens it often happens in bursts. When we restart the computer it may crash immediately upon logging in (and by crash, I mean the monitor shutting off) and this could happen 2-3 times in a row.  I updated to the newest AMD Catalyst drivers to no avail.  Here are the specs of the PC:

 

Gigabyte Radeon HD 7870 GHz Edition

Intel i5 3570k

MSI Z77A-GD41

WD Black 1TB

Rosewill Green Series RG630-S12 630W 

Corsair Vengeance 8 GB (2 x 4GB) low profile

all running on Windows 8

 

Some extra situation information:

• The first time we experienced this bug we got a "missing operating system" error, but I believe this was only because we had a USB plugged in when we rebooted the computer, and had forgot to change the boot priority.  
• After we recovered from the missing operating system error, and rebooted the system a second time when the screen turned off again, I noticed the screen blink from on to off and back again, followed by a "display adapter has stopped responding and recovered" message, so I am wondering if this problem is caused by the display adapter crashing but not responding?
• It is not only crashing while running games (actually I don't believe it has crashed during a game yet) which is why I don't believe this is a voltage/over heating issue. (The card is at stock speeds anyway)
• It may also be worth noting that when we reboot the computer after a crash, nearly every time it says windows is updating before allowing me to log in.  This may be unrelated completely (fresh install of win 8, its gunna have some updates to do in order to catch up), or possibly windows is attempting to reboot the computer, but only shutting down the display adapter and getting stuck on that? (You can tell I'm running low on ideas by this point)
• PS: its not actually a monitor, but a 720p TV running through HDMI. Doubt this matters though, I'm just trying to be as thorough as possible   

 

Any help at all would be appreciated, really hope this does not come down to me RMA'ing the card and finding out the card wasn't the cause in the first place.   

[HEXiT]

after re-reading i realized i made a mistake in my advice... 

try another lead, and try another screen. if the screen stays on for either than you have your answer. 

even a new monitor can be faulty so dont discount that its damaged just because its new.

the display adapter quitting normally means a bad driver install. so download the latest from your manufacturers website and try them. you can also try using older drivers as they can be more stable than the new beta 1s.

[mgsstar]

Did you try a different monitor to see if that happens? When it gives no input, did you try unplugging the monitor and plugging it back in to see if it detects it? I would try a fresh reinstall of drivers by uninstalling and cleaning the remaining registry keys with CCleaner. If that doesn't resolve it, I would do a fresh install of Windows to make sure that your Windows isn't corrupted and is causing these problems. The crashes might have corrupted your system because of every time a crash happens it tries to update after a reboot.

[KYJelliott]

That is the strangest problem I've seen in a while. sometimes what is causing the problem can be the most unlikely thing. My advice would be to try it with a dvi connector and a computer monitor, see if that fixes it, if so great, if not, then my advice would be to uninstall everything and do a fresh install to see if that fixes it.

[diiPex]

When the screen turned off I did try unplugging the monitor and plugging it back in but it didn't fix the problem.  Next time this happens I'l try plugging in a different monitor via DVI to see if that fixes it.  If this doesn't work, I'l do a fresh install of the graphics driver, and I'l repair the windows installation.  
 

Thanks for the help, I'l this thread updated with what happens.  

[BroKenFingers]

another area to look at would be any power saving settings on your system..and in the 720p TV..just to rule that out..