Numerous reasons why a computer will not boot.
Make sure all cables (including CPU ATX_12V supply), DIMM's, and video card are installed properly.
The FX-8350 CPU requires BIOS version 1401 or later to be installed/flashed {If necessary, use a lower/earlier version of CPU to temporarily boot the computer and flash the BIOS to later version, then re-install FX-8350 CPU}.
Possibly the PSU, DIMM's, video card, or motherboard faulty.
Try another PSU (at hand or borrow one).
Try using ONE DIMM at a time and in different slots.
Try using integrated graphics instead of video card.
If all above fail, then the motherboard may be faulty.