Mac pro 2008 won't turn on
So, I got a new gpu that turned out to be incompatible, so I removed it. When I turned it back on, it wouldn't turn on after I press the power button. It is receiving power. I can only get power through if i take the cr2032 battery out, plug it in, and put the battery back in. If I do this, then the Err A and Err B lights come on. When i press the diag button on the logic board, it gives a yellow light on the stby led. Any help would be appreciated greatly.