System not displaying anything

[Hotbbqwing]

Current Build:
Gigabyte 970 UD3
Gigabyte r9 280x factory OCed
AMD 8350
Corsair RM 650

Hello,
I recently upgraded my graphics card and cpu, and while playing BF3, my system completely cut out. I tried turning it back on, but absolutely nothing happened. After some checking, I decided that it was my PSU that had gone out, which was a coonix 700w at the time. Today, I bought the PSU currently in my system, and after putting it in, I was at least able to get my system fans and CPU watercooler to spin and light up. When I connected my graphics card, which is connected with an 8 pin and a 6 pin, the fan spun for about a half a second, then stopped. I decided to put in my old card, a gtx 560, which is two 6 pins, and the fans at least continuously spun on that, but when I plugged in my monitor, it did not display anything. Could the CPU have burned out? Because the motherboard supplied power to the fans and watercooler, I am assuming the motherboard still works. Also, should I check to see if the 280x will work in my friends system, before RMA'ing it?
Thanks,
Hotbbqwing

 

[rolli59]

Yes check the 280X in the friends rig, everything points to the motherboard if neither GPU works. It is very rare anything happens to CPU's.