Disabling Duel Display

I usually use my Macbook Pro loptop screen and an external monitor. now away from home, I need to just use my loptop screen. I am trying to use iDVD and the program is running, but I can not see the screens. It is as if the computer still thinks I am hooked up to the other monitor. Any help?

have you tried using expose to see if that brings the iMovie window back to centre stage

Thank you...I tried, and it still did not work, but I am also not very familiar with Expose.