Blurry / soft video from WMP9 codec

I know that this is probably a characteristic of the codec but I would like to reduce the softening of edges that is produced by the WMP9 codec without getting crazy sized files.

I compile a lot of industrial style videos for customer training and use WMP9 for compatibiltiy reasons. Maybe the softening isn't so important for general video but with so many sharp edges and high contrast images, it always appears that the PC projecto
r is out of focus.

Is there any tweaking I can do in the codec (maybe in Windows Media Encoder) that might help?

Typically I am encoding to two different resolutions and bitrates
2.1Mbit 640 x 480
512kbit 320 x 240

The results I get when expanding both files to full screen are not so different, I am looking for much better performance from the 640 x 480 resolution.

archie