Hardware Issues, not sure how to troubleshoot

Im having many problems with a new PC build. After installing all the parts, I tried booting but wasnt getting any power to anything. I unhooked everything and tested the PSU by shorting the 24 pin connector (green and black wires) and It came on fine. I hooked everything back up and tried powering on, nothing happened. I shorted the 24 pin connector yet again WHILE it was connected to the MOBO and everything started up fine (the fans for the case, GPU, and CPU all spun fine). I booted up the PC and got a "no signal" message on my monitor. I searched many forums and tried resetting and cleaning RAM and GPU and still had the same problem. I eventually found a solution by holding the front case power button for 30 seconds while the PSU was turned off. I finally got to the BIOS screen and after setup, everything seemed to be working fine (with the 24 pin connector still shorted). I tried playing a game and as soon as it launched, the PC crashed. I restarted and was sent back to BIOS. Now the PC wont boot from my DVD/CD drive OR the HDD, no matter which has priority. I removed the CMOS for a few minutes to let it reset to try starting over from scratch. When I put the CMOS back in, I was getting the same "no signal" message and this time the 30 second power button trick didnt work at all. Currently Im getting no power to my mouse, keyboard, or monitor (the monitor stays in sleep mode instead of coming up with a "no signal" message) but all fans are running and the front power light comes on.

SPECS
Motherboard: GIGABYTE 990FXA-UD5 R5
CPU: AMD 8320 Vishera 8-core
GPU: MSI GeForce GT 730
HDD: WD10EZEX 1.0T SATA 64Mb (pulled from an HP computer, had windows 8.1 already installed)
PSU: Logisys 550W (generic PSU)
DVD/CD Drive pulled from the same HP computer mentioned above

Ive searched through pages and pages of forums and tried every possible solution and still no permanent solution. Im willing to try anything except buying new parts, everything I have is brand new with the exception of a couple of pieces that are less than a month old and everything has worked fine within the last 48 hours. Please help!
 
A lot of people forget to connect a 4 or 6 pin connector near the CPU. This is the 12 volt aux connection. It is needed to start the computer
 
A lot of people forget to connect a 4 or 6 pin connector near the CPU. This is the 12 volt aux connection. It is needed to start the computer

I have it connected. Its an 8 pin on mine and my PSU has two 4 pin connecters that combine to make the connection. Like I said, it was working fine yesterday and once I launched League of Legends and got in to a game, it crashed and now I cant get anything other than the internal hardware to power up
 
So it must be a hardware failure. How is the bios configured?
Not sure, all I know is the HDD is the primary boot source and it worked fine. Everything else is "recommended optimum" settings. How do I determine which component is failing? They all power up and run fine from the looks of it. All the fans for each part work. Im guessing its the motherboard since the 24 pin connector has to be shorted to make it run and I dont get power to the mouse, keyboard, or monitor
 
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