Hi, I just bought a used Mac Pro 1.1 and hooked it up. after a few min it froze on me. I was able to move the mouse but the screen completely froze. I couldn't restart or force quit. So i held down the power button to shut off and restarted it that way. After a few min, it did it again. I've installed all the updates and it still does it. It also shows black lines across the screen sporadically. Heres a screen cap the ATI 1900 Card is in it. Any info would be greatly appreciated!