"The windows mediaplayer will play the avi file "IF" your graphic card supports the codec."

News to me! I always thought the idea of Windows was that the specific hardware of the graphics card was hidden behing the drivers for the card, and that the drivers should all support common functionality. If the graphics card does not provide hardware support for a specific feature then the drivers should emulate that in software; the issue becomes one of performance.

Without hardware support some types of encoded video will play back so slowly as to be useless.

I've got a pretty crummy graphics card yet all my video playback problems have so far been traceable to the lack of a suitable codec. If I can get a codec then I'm OK.

I would expect ".wmv" files to play back without problems. Certainly ".avi" files are much more problematic. Windows Media Player has an option you can set so that it tries to automatically download codecs for unknown file formats; I can't say I found this to be very successful, however.