My PC is running Windows 7 64-bit with onboard Realtek HD Audio. I've checked all obvious places, Device Manager, Volume Control, RealTek HD Audio Manager, etc. I've tried a dozen different fixes involving regedit, services.msc and uninstalling drivers, updating drivers, rolling back drivers, etc. I uninstalled the free version of AVG Anti-Virus because I found someone who linked their similar issues to that. I've installed Microsoft Security Essentials (because it rated high on this website) and run a Full Scan just to see if it was some malware or virus. Came back clean. Out of desperation, I bought a Sound Blaster X-Fi Go! external sound card and disabled the onboard audio in BIOS and uninstalled all related sound card crap I could find before installing the X-Fi drivers. Still the same issue. iTunes simply says "iTunes has detected a problem with your audio configuration. Audio/Video playback may not operate properly." iTunes then loads fine but will not do anything when clicking Play. I've uninstalled Quicktime with no results. All games, YouTube, Mozilla Firefox 12, IE 9.0.6, Windows Media Player 12 are silent. I have Adobe Audition and it simply does NOT show any sound hardware available. So I know it is not a hardware issue. I haven't played in Windows Tech World for a few years but I've tried everything I could think of with no success. I searched all the threads here that sounded remotely similar with nothing near to this posted. Any suggestions or solutions would be greatly appreciated! I'd be glad to provide any other information... my PC is less than 3 months old.