Playing a DVD is not native Windows. I suggest you start with reinstalling the DVD-playing program. If you're lucky, both that program and iTunes work. If you're unlucky, post again with more details.
My DVD drive had been working well UNTIL recently when I installed iTunes for my iPod Mini. Now, whenever, I try to play a DVD, I get the "blue screen of death"!!! Has anyone come across this problem and is there a very simple solution? Other than get rid of iTunes and the iPod?