At Demo Overview the WMP guys offer several "demos" purported to demonstrate the superiority of Windows Media Player over other audio/video players and formats.

The intent here strikes me sort of as a "who cares" kind of thing, however -

If you really are using WMP and are having trouble, the demos might help you sort out which kinds of downloads might work and which ones won't work on your setup. Be aware that most, but not all, of the demos carry the note "requires a high speed connection." The demos also are intended to show the latest (WMP 9 and later) doing "really great" stuff, so they may not be fully representative of "ordinary sources."

Those using alternative programs/codecs might be able to try out the demos there to see whether their program really does do "everything" that WMP claims to do. Of course they may have rigged them to play only with WMP. I have no idea whether the demos may look only for your WMP or whether they'll work with another player.

Not a recommendation. Just a note that it's there.

John