E171FP problem playing DVD (image streched from time to time)

Hello,

I just bought a Dimension 4600 with a E171FP display. The way things are displayed is perfect as far as standard applications (explorer, word, excel, ...) are concerned.  The problem is when I am playing a DVD : when the image is moving fast, it sometime produces a strange effect as if the image was streched (remaining too long on the screen, distorsion ?).

Has somebody already experienced that ? What could be done to improve this ? 

I am running Windows XP Home Edition in French. I about sure that I didn't change anything in the configuration concerning the display.

DVD model : HL-DT-ST DVD-ROM GDR8162B, with driver cdrom.sys

Graphic card : NVIDIA GeForce4 MX 440 with AGP8X (Dell)  with driver nv4_mini.sys

Resolution : 1024 x 768

Thank you very much for your help.