Please can anyone suggest how I can fix this problem? The error message appears when I try to play an mp3. It might be related to the problems that I have had recently with the Mostrar Dialer, as Windows Media Player 9 behaved OK before that. Error message 'Windows Media Player cannot play the file because there is a problem with your sound device. There may not be a sound device installed on your computer, it may be in use by another program, or it may not be functioning properly.' More information '0xC00D11BA: Cannot play the file Windows Media Player cannot play the file because there is a problem with your sound device, such as a sound card or sound controller. You may encounter this error message for one of the following reasons: *Your sound device is in use by another program. Quit other programs that may be using your sound device, and then try to play the file again. *Your sound device is not functioning properly. To troubleshoot the problem, see the Sound Troubleshooter in Windows Help or refer to your sound device's documentation. *You do not have a sound device installed on your computer. Install a sound device, and then try to play the file again.' I don't know if it's relevant, but I'm also running Creative SB Live! version 007 (with 1024 Synth Voices)(driver for SB Live = C:\WINDOWS\INF\VSB010X.INF). Update - - I re-installed both Creative SB 5.1 and WMP9, but still couldn't play mp3 files anywhere. Having looked at some other forums warning against wmp9, I started wondering if series 9 of the Windows Media Player is the problem. I really don't know. Anyway, I "rolled back" to Windows Media Player 6.4, but the problem is still here. Music CD's - They are working fine in CD player (the little one that comes with windows 98) and Sound Blaster Creative Playstation 2. Music CD's don't play in Media Player 6 or WinAmp. No idea what is playing wav files. The only programme that I can get to play midi files is Windows Media Player 6.4. I can't get any of this kit to make MP3s play. When I try to open an MP£ in WMP6.4, I get the 80040256 error msg. Has anything like this happened to anyone else? Is there a bug-fix utility that I can get to straighten out the problem? Any useful ideas would be gratefully received. In addition, I'm now getting an eror msg saying msgsrv32 is not responding.