Does all audio play fast?  For example do Audio CDs, and mp3s on your hard
drive both play fast?

From ZachD's most useful WMP FAQ (http://www.zachd.com/pss/pss.html)
<quote>
Q: Why does WMP play too fast or too slow?
A: We use the audio clock from your sound card to time things, and it's
not working correctly.
Per Patrick: This sounds like a problem I've seen on some sound cards.
Please try reducing your audio hardware acceleration level in the 'Sounds
and Audio Devices' control panel. After opening the panel, click
'Advanced' under speaker settings, then 'Performance' and try moving the
hardware acceleration down to different levels. I'm looking at my XP
machine, so the buttons may be a little different in other versions of the
OS. [Note that you can also access the audio hardware acceleration slider
in the app "dxdiag.exe" (already on your system) on the "Sound" tab.]
Please note that by reducing hardware acceleration to none, you will lose
any 5.1 audio support your sound card has (if any).

If that doesn't help, see "I'm having sound problems"
(http://zachd.com/pss/pss.html#dsound) for how to fix this.
</quote>

In Win Me the audio hardware slider is found at: Control Panel | Sounds
and Multimedia | Audio - Sound Playback | Advanced where you should now
see two tabs.  The slider is on the Performance tab.