What version of windows are you running?
If XP go into the start menu then go to> control panel >performance and maintenance>system>hardware> device manager and looK at the sound devices and see if they are all seen as operating OK (no yellow exclamation marks). If it all looks fine there try uninstalling the sound device from there, reboot and see if windows picks it up.
If XP go into the start menu then go to> control panel >performance and maintenance>system>hardware> device manager and looK at the sound devices and see if they are all seen as operating OK (no yellow exclamation marks). If it all looks fine there try uninstalling the sound device from there, reboot and see if windows picks it up.