I have a Dimension 8400.  Even with brand new Dvds I will get slight pauses during play.  I use PowerDVD, but have tried playing discs through WinDVD and Media Player.  I've also tried watching Dvd's on a second drive in the computer and have the same problems.  My system should have more than enough power to handle this.  I don't have any antivirus programs running in the background or anything.  Any help?