Static from speakers

I get static from my speakers when playing downloaded movies and dvd’s. I dont’t hear static when playing music CD’s. I cant’t say it’s my speakers because the music plays fine. I am using a sound blaster live sound card with the latest up dates. This problem is driving me crezy as my wife and I like to sit in out computer room and watch movies. What can the problem be? I would appreciate any help I can get. Thanks