Hello, 

In the past month I've sent my motherboard and GPU for a replacement because I thought it might have been one or the other that is causing the error code 99. So my MB and GPU are new. Also I've used the same hardware for the past year without any problems until recently. Fortunately, the onboard graphics does work.

I've tried installing my current GPU along with other working GPU's on different slots of my MB and the error code still persists. I know to flick the switches on the MB to enable to use of the different slots so we can rule that issue out.

Does anyone have an idea what this problem may persist to?