My new build will not boot with my 2006 Apple Cinema 23 inch Display plugged in to the DVI Port. It has been driving me mad. I suspect that the monitor is not HDCP compliant and was wondering where HDCP is enforced. Is it by the OS or is it done by MSI in the BIOS or somewhere in their firmware? If in BIOS or somewhere else at the motherboard level, it is possible that this is causing the problem.
To the best of my knowledge, HDCP is done at the video card level. However, it should be able to fall back on a non-HDCP mode if needed, and the only time you'd even notice would be when you tried to play a bluray movie and the player software didn't detect the HDCP encryption. For just your average desktop type uses, it shouldn't be an issue.
Those older Cinema Displays were kind of notorious for just up and dying. A lot of times the power brick goes bad, other times it's the logic board. They do offer some minimal amount of diagnostic help in the form of the LED on the front. It should be strobing in a distinctive pattern which you can then look up on Apple's support site to at least get pointed in the right direction. If you're not even getting that, I'd suspect your power brick died.