Can't boot computer with new Radeon RX 560 video card

[kmrobert]

I recently got a new radeon rx 560 gpu to update my existing radeon hd 6970 graphics card. However once I have it installed my computer won't boot, and the VGA LED on the motherboard turns a solid red. From googling - I haven't found any issues with incompatibility with motherboard or CPU so I'm a bit at a loss. I was surprised that the rx 560 doesn't have 6 or 8 pin power connections, but I guess that's more common now?

My computer specs:
ASUS Sabertooth 990FX
AMD Phenom II X6 1100T
Corsair Vengeance 2x8GB DDR3
XFX PRO750W

I've tried removing the CMOS battery, trying other PCIE ports, and I'm running out of ideas. So any thoughts would be appreciated. The only other thoughts I had were either the card was DOA, or issues with PSU, however I would think 750W would be enough.

 

[kmrobert]

Actually got it fixed. Apparently the main issue was i had to update my BIOS. Once I had that, the system recognized the card and got it working.