Dvd Jittery Problem

If i play copied DVDs on my Pc most are fine but then i get the odd few which jitter and crackles, i was wondering how could i fix this cause the copied DVDs i just bought i need watch on my comp cause my ps2 has buggered up.

Try Cyberlink Power DVD 7 it's the best Player for the PC

http://www.cyberlink.com/multi/products/main_112_ENU.html

Also, make sure DMA is enabled. It's on the device manager.