choppy dvd playback

I've got a computer dual booting win98 and ubuntu 7.04. My purchased dvds play fine in ubuntu but are all choppy in win98. The computer has 320m ram, but is old (celeron coppermine 566) and DMA is checked in the device manager. Since the dvds play well in ubuntu, I don't believe it is a hardware issue anyways. I use mediaplayer classic (with k-lite codec pack) in win98 for all my video watching - it plays .flv .avi .mov and .wma files excellent. I would just like to be able to watch EVERYTHING on one player/os.

Also, I have another box running winxp. The same dvds I was having trouble with in win98 play flawlessly in xp (also using mpclassic with k-lite).

Thanks for any suggestions.

 

Have you tried updating the sound driver in 98 ? .