Question Diagnosing my "dead" PC

[imjimjim22]

I have a PC that is broken and I plan to fix. It broke when I bought a fake 750 ti off of Ebay and was stupid enough to put it in my personal rig. I was trying to revert it back to a 550 ti because it was a 550 ti with a flashed bios, and all of the sudden my build shut off and would not post for anything. I tried rebuilding the PC, replacing CMOS, using internal graphics, and all to no prevail. I just ask that someone please help me diagnose my PC. I plan on upgrading it to maybe an RX 580, MSI Gaming 970 Mobo, FX 8350, a watercooler, and a new case that supports watercooling but I don't know what to buy first just to get it to post.

MY BUILD
AMD FX 4300
ASUS M5A78L-M PLUS/ USB3
8gb PC3 12800 (Samsung)
GT 730 (At the time of it breaking it was a GTX 1060 6gb but I sold it for extra money after it broke)
Corsair Carbide Spec-04
32gb SSD
1tb HDD
500 Watt Cybertron PSU

 

[rgd1101]

don't waste money on FX-anything.
try another working psu?