Science or Hex ... new MSI Gaming 970 breadboard won't always post with good components

[kingofcoins]

Never has this stopped me before, you ? ..>The Mobo power pins do not work for jump start, so the green psu wire is closed to boot board.
I am building a gamer with a new MSI 970 Gaming board, and new EVGA 600 watt PSU and as I always do, set up a pre-build test breadboard with known working good DDR3 4gb memory and ATI Radeon HD 4600 video card, both from this Apple I'm typing on, also attached a speaker. Now the setup refused to post or beep but after cable and reseating checks and tries it started beeping 5 times so I added a new Phenom II CPU. Again it refused to beep or post but for some reason it did post with no beep and I added my working Win 10 HD, then it refused to post for many more tries but after reseating a RAM card it posted and Win 10 black screened, so I accessed the bios to set date and time and check video and boot datas. After saving and exiting I killed the power, now it refuses to post or beep, although board lights up and all fans work. I have made repeated swaps of all parts except mobo with parts from working computers, and reseated all to no avail. Reseting bios, changing battery, testing the PSU gray wire, moving ram, nothing has not helped.
My questions are...
1) Is there a circuit continuity reason why the power pins don't start the psu ?
2) Is there any logical reason why it will post, but then will not post ?
3) AT this point I'm open to any suggestions short of your board is cursed ..thanks.

 

[Ralston18]

Clarify:

" ....set up a pre-build test breadboard with known working good DDR3 4gb memory and ATI Radeon HD 4600 video card, both from this Apple I'm typing on "

Apple?

Intermittent behavior tends to be due to a loose/faulty connection somewhere.


And use the motherboard's manual to look up the beep codes/beep patterns (i.e., 5 beeps). The beep code should be helpful.