Strange Video Corruptions

I'm having a strange issue with watching video. Whenever I watch a DVD I get a mass of green dots and lines all over the video. This is a screen shot while I was watching on a DVD.
http://i44.tinypic.com/1zr156t.jpg
I have this problem in Windows Media Center, WinDVD and in WMP (10 or 11). However, when I watch the DVD with VLC Media Player, the picture is totally clear. The same problem happens when watching/recording TV in Windows Media Center.

Whenever I just play a regular video file, there is less of a problem but I still get vertical dotted lines across the picture, like in this shot.
http://i39.tinypic.com/2dqldex.jpg.
This problem also exists in Media Center, WMP, and in iTunes and Quicktime. However, in VLC Media Player there is again no problem.

I'm running a Sony Vaio VGC-RB57G with fully updated Windows XP MCE SP3, 2x 2.80 GHz Pentium D CPU, 2 GB DDR2 SDRAM @ 533 MHz, Radeon X300 Series Graphics Card, and dual monitors. One connected via DVI and the other via standard SVGA. The problems are identical on both monitors, whether one or both monitors are enabled, and no matter which is set as primary.

Does anyone have any idea what the problem might be or what I can do to solve it? Thanks!