Why are using PowerDVD that software decoder, and WinDVD are both garbage
decoders. You're video card is a bit old too. For just a little bit of money
you can upgrade to the GeForce 4MX card line, and experience better DVD
playback because those cards have DVD decoding built into their hardware.
But if you're not look for an upgrade you can always try Sonic's DVD
Decoder, also bundled with the Sonic CinePlayer. That's the best software
DVD decoder available using less CPU processing, and performing better than
any other software decoder and even some hardware decoders.