DVD sound distorts, fades in and out

[solidius]

I'm not sure if this is a hardware issue or not, but Whenever I try to play a DVD in my laptop, the sound gets all messed up. It fades in and out, distorts, and makes WEIRD noises related to the distortion I assume. I can watch ANY type of video file and not a have problem, even watch AVI's burned onto a DVD, but whenever I try to put a DVD in the sounds gets all messed up. I just recently got an I/O magic external DVD burner, but I haven't played DVD's in my laptop for about 2 months so I don't know how long this has been going on. However I'm not sure this is related because there was no install software. It works as soon as you plug it in basically. Plus I tried unplugging the DVD burner and I still get the same result. Anyways, ALL help is appreciated.