System:
Gigabyte GA-EP45-UD3R
Intel Core 2 Duo E8400 Wolfdale 3.0GHz LGA 775 65W Dual-Core Processor
4G RAM
XP Home SP3 (Clean install and updates)
WMP11
Roxio Easy Media Creator 8.05
XFX HD-477A-YDFC Radeon HD 4770 512MB 128-bit GDDR5 PCI Express

Before I install the ATI Catalyst driver (9.11), mpeg2 files play with no problem in WMP11. I can also play mpeg1 files and DVDs.

After I install the drivers for the graphics card, mpeg2 playback is pixelated with green flashes. Everything else plays with no problem. I say it is a driver problem, since the playback worked before installing the drivers. ATI says it is a codec problem.

VLC media player works after installing the driver, but the video quality is not as good as WMP (before the driver is installed). I would like to get WMP to work.

This is my fifth system build and I have never had a problem like this before. This one is driving me crazy. I would like some specific troubleshooting suggestions, a specific codec, how to make sure WMP is using a specific codec, etc, not just install a bunch of codecs and see what happens. I'd like to know how to solve the problem.

Thanks in advance.