Hmm, you should be doing command-alt-P-R instead. The above command resets the PMU. Though that should wipe out the NVRAM as well (which is what the key press I mentioned does... only).
Try deleting the file /Library/Preferences/com.apple.windowserver.plist - it seems to have a reference to the display to use. It might solve your problem. You may have to reset your display prefs after deleting that file; just warning you.