That's why I asked you if the codecs show up for the video codec in virtualdub. You installed a ton of concurrent codecs, maybe your system configuration is messed up now. Playback is different from encoding, Playback through media player usually uses direct show, encoding is done through the VfW-Interface IIRC. Please check if you can encode in divx with virtual dub. If not, you'll have to clean up your system and fix the registry entries until it works.