No Video, "never Turn Off Display"

I recently had to reinstall Vista after a HD failure. Almost everything is working as expected. I do have tasks that I want to have run for long periods of time (usually overnight). I have set my power options to "never turn off display" and "never sleep". Screensaver is set to "none"

This works for shorter periods of time, but when I leave the PC overnight, I come back and my monitor indicates that it is getting no signal. The PC power lights are still on, but nothing I do turns the monitor feed back on (keyboard and mouse input have no visible effect). This is not a monitor sleep issue, I have confirmed that it is not recieving signal from the PC.

I've tested this even when my tasks are not running, so I know it isn't related to that. Also, I didn't have this problem before the reinstall. I'm concerned because the only solution is to cold boot, and that would be bad if the PC happens to be in the middle of a task, or a windows update or something. Other than the power settings and screen saver, what else should I be checking in Vista that might create (or prevent) this type of behavior?