Sorry, I thought you meant after you had quit the DVD. VRAM is the block of RAM that stores the video data before it activates the monitor--it's not just a real-time flow to the monitor.
If you're still playing the DVD and getting this same loop, get it outta there, and then try (a) turn monitor on and then off. If no joy then (b) shut machine down fully, rest it for three minutes and then boot it up without the DVD in place. Should clear the air...