windows Media player recurring error

Hi..

I have a dell inspiron 6400. Until recently, Ive been having problems with playing dvds on it. They would play choppily. But with  help from the DVD support section, I fixed it. Earlier, when I had the problem of choppy video, My Windows Media player stopped playing dvds. Whenever I'd put in the DVD, it'd say " WMP has encountered a problem and has to close." It only plays music. Even now, after fixing the problem of choopy video and audio, WMP doesn't play the dvds. What real;y is wrong?

Thanking you.