Posted 14 July 2010 - 12:15 AM
Unfortunately, a common issue with rogue AVs. Go into device manager, click View->Hidden Devices. This will show system devices that are usually handled during Windows install. It will probably drill down automatically to reveal a conflicting device. Try to automatically update the device. If it doesn't work, or if doing so doesn't fix your audio problem, don't fret. If it doesn't find a driver for it, just delete it and reboot. At post, if your sound card is onboard, disable then re-enable it. When back in Windows, go back into device manager and scan for new hardware.
This won't fix it every time, but is the easiest fix, and works about 90% of the time. If it doesn't work, let me know, as there are some alternate (albeit more annoying) fixes for this.