Distorted Audio (from DVD)

I have been renting DVD's for a few weeks now and they have all played on my PC and been ripped to DVD perfectly. I now received Kill Bill v.2 and The Godfather. Both of these, when I play them on my PC come out with very distorted sound (video fine). I can still hear all other audio perfectly from other sources but only these DVD's come out funny. The DVD works fine on my DVD Player and my laptop but not on the PC with the DVD Burner.

Soundcard drives?
Codecs?
Loose leads?
Bad speakers?
Bad Drive?

I've done a few more tests;

I have one DVD-ROM drive and one DVD+RW drive in my PC

When I play from my DVD-ROM drive the sound is distorted but when I play from my DVD+RW drive it is fine.

Does this mean I need a new drive, or is it fixable

Need more info, Drive names, model numbers, any info you can give?

LITEON DVD-ROM LTD163 (DVD-ROM)
NEC DVD+RW ND-1100A (DVD+RW)

After all the tests it seems that it is the Liteon drive that is the problem.

Can this be fixed or do I need it checked, or simply replaced?

Does anyone know if it can be fixed?