I have a MacPro 1,1 (flashed to 2,1) Running 10.10.5. I installed the latest Nvidia web driver, in preparation to install a GTX 970 (i have a ATI 5770 in now). After the web driver installation the computer won't restart, but if I shut it down and power it back up its fine. It only happens if I hit restart, the computer turns off then never fully powers back up. The hard drive spins up then spins down, no chime and keeps doing this. But a shut down and power up is fine.