New PC turns on, but has no display and turns off after ~10 seconds.

[FoxxyRin]

As the title says, I just finished building my boyfriend's PC. It turned on just fine when I benched it and everything seemed okay, so I went ahead and got everything put together. Well, the PC seemingly turns on just fine, but the display refuses to work. We've tried both the onboard port and his gpu port and that doesn't fix it. Ontop of this, the computer turns itself off after about ten seconds. His PSU and GPU are both from his old computer, so I can confirm that they work just fine, though I am planning to replace the PSU in a week or two anyway since the current one isn't the best choice. Anyone have any idea what to check first? I've re-seated and checked all of the cables, and everything seems good. I'm just overwhelmed with what to do.

 

Part List: http://pcpartpicker.com/user/FoxxyRin/saved/zXLgXL

(Note: He has a temporary 5750 installed for the moment, as his normal card is being RMA'd.)

[sushisharkjl]

3 minutes ago, FoxxyRin said:

As the title says, I just finished building my boyfriend's PC. It turned on just fine when I benched it and everything seemed okay, so I went ahead and got everything put together. Well, the PC seemingly turns on just fine, but the display refuses to work. We've tried both the onboard port and his gpu port and that doesn't fix it. Ontop of this, the computer turns itself off after about ten seconds. His PSU and GPU are both from his old computer, so I can confirm that they work just fine, though I am planning to replace the PSU in a week or two anyway since the current one isn't the best choice. Anyone have any idea what to check first? I've re-seated and checked all of the cables, and everything seems good. I'm just overwhelmed with what to do.

 

Part List: http://pcpartpicker.com/user/FoxxyRin/saved/zXLgXL

(Note: He has a temporary 5750 installed for the moment, as his normal card is being RMA'd.)

Reset the CMOS? 

Your mobo may be dead if it's not POSTing.

[FoxxyRin]

41 minutes ago, sushisharkjl said:

Reset the CMOS? 

I feel like an idiot for not doing this first. It fixed the problem. I shouldn't build PCs while exhausted, lol.