My computer recently stopped streaming music from Napster randomly. After a quick Google I found it may be something to do with my Streaming proxy settings in Windows Media Player.

You need to make sure that on the Player tab, 'Connect to internet' is ticked. Then untick RTSP/UDP under network.

If you're streaming proxy settings box is blank, delete the file WMSDKNS.xml in C:\Documents and Settings\Your Username\Local Settings\Application Data\Microsoft\Windows Media\11.0

For more detailed instructions on the above please visit my post about it here: Napster won't stream songs anymore