HPE-510t does not boot with AMD FirePro W5000 (Windows 8.1)

I just purchased an AMD FirePro W5000 (TDP = 75 W) to replace my nVidia Quadro 600 (TDP = 40 W) in my 2011 HPE-510t (i7-2600, 12 GB RAM). Dell U2913WM monitor.

My machine will not start with the new card inserted. I upgraded the stock 300 W power supply to a 450 W Antec VP450F, but that didn't change  the startup situation. I tried DisplayPort and Dual-Link DVI-D.

Anyone been able to get the AMD FirePro working in an HP desktop of this generation?

Thanks,

Mike