At some point I became unable to play music on Windows Media Player. It pops up a window telling me that I have no sound card or that it is not functioning correctly. I have uninstalled WMP and reinstalled it but that did not help. I have Winamp installed and it works fine. Anyone have a suggestion to correct the problem?
check your sound drivers at my computer / properties / device manager and reinstall the drivers as necessary.
I second sailor’s suggestion but be sure you first un-install any sound card drivers listed in the add/remove programs applet and delete/remove the applicable sound controllers listed under the System Properties device manager listing to allow for a (relatively) clean re-install.
Thanks for your help. Of course, I knew that. I was just testing you. 
Seriously, I appreciate the advice.