Might be several methods, if it's still visible in device manager you can enable there. Alternatively in device manager after selecting it an option will appear beginning with drivers, at the bottom of that window should be option to remove/uninstall completely. A reboot after that should cause rediscovery of the device and a fresh install. You may or maynot need to uninstall sound software and reinstall as well.
After removing an existing component which is enabled in bios from device manager then shut down and then restart. The system should automatically redetect the device and begin reinstallation (I referred to this as discovery) sorry for the confusion. Just for a refresher its (click) Start/control panel/device manager, select sound device in question and right click on it.