Is my CPU Toast?

[timairborne]

Hey thanks for the help in advance, I am trying to troubleshoot my brothers PC atm and its giving me an aneurysm. His PC wouldn't display or even post anymore suddenly, we thought GPU, tried his card on my PC works just fine. I have swapped everything off his to my working hardware and nothing solves the problem. I have eliminated the GPU, PSU, HDD and we bought a new motherboard still wont display or post. We got it to post and load windows normally with display one time using my card on his new board. Subsequent attempts at the same thing have all been fruitless.
What happens when I got everything set up and ready and turn on the board is the lights and CPU fan turn on, HDD spins, but the GPU fans (both cards) refuse to start and then the build just sits there doing nothing no post no display nothing.
Normally this would be easy to figure out but that one boot that worked as well as hes taken it to micro center and they told him it was his mobo. Personally I think the micro center guy was full of it but I don't want to send him on a buy this buy that buy this adventure unless I'm sure.

His hardware:
msi 970 gaming mobo (brand new, giving same issue as old mobo)
msi r7 370 4g gpu (i tested his build with my gtx 970 and thats when we got the one and only boot)
amd fx 6200 cpu (only thing im unable to test due to chipset)
460w power supply (i tested my 650w psu and still wont power up the gpu/post)

If anyone has any ideas or suggestions please let me know.

 

[Yamitime]

do u have a speaker attached to the motherboard for the error beeps?

 

[timairborne]

I do not have a speaker. I can look in some of my old cases and see if they have one.