You don't have some kind of DSP software installed do you? Ie software that lets you set your Pc to sound like an auditorium, jazz club, disco etc. If so and it has been activated this can lead to odd effects with sound the PC processes like recorded music or DVDs, but not that it directly plays back, like when you insert a standard music CD. If you have it, turn it off.
If you can, have you tried turning the output from the PC (ie. the sound control on the software) down, and the external control on your speakers up? It could be that the sound level from a DVD is higher than that from the Audio, so when you play a DVD you get some distortion.
If you have 2 or more drives, have you tried playing normal audio cd's through the DVD drive? At least that would rule out a bad connection internally if you didn't get any crackles.
Thank you all for your help, i think the problem is something silly, as it did it with cds as well, but i saw something in one of the computer books and it resolved it on the cds. It was something to do with burning cds and not getting perfect sound, but do you think i can remember what i did and i canot find it in any of my books.
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