Resolved 2006 Mac Pro - Flashed 2,1 won't reboot

[Ih8reno]

I recently received a 2006 Mac Pro with upgraded 2xquad 2.66GHZ processors. I wanted to install Snow Leopard which went fine. But when installing updated it goes to reboot and then either goes to a black screen or has sometimes made nose like the dvd drive was trying to spin up but then stops and tries again. Any ideas? I've tried resetting it from the button on the motherboard.

 

[ITguy2016]

Is there a disc in the optical drive? If so have you attempted to remove it (hold the mouse button down while the system starts)? It appears the system was working fine until updates were applied? Is that correct? Perhaps the hard disk is failing? What bootable devices show up when you hold the Option key on boot? Have you attempted the standard "remove all that is unnecessary to boot the system" step?

 

[Ih8reno]

Took out piece by piece until it seems to boot fine. Ram seems to be the problem. Now running only 8GB instead of the full 12GB I had. Thanks