Sounds to me like you have two sound drivers running. R-click the speaker icon in the bottom right system tray. L-click playback devices. If your not running digital desktop speakers(either through digital coax or fiber optic) and/or digital speakers integrated into a monitor (HDMI), there should only be one device (probably Realtech or Via) in the list labeled as the default, entitled "Speakers", under the Playback tab. If there's more than one, then that's probably what's causing the problem. It's hard to give specific info; since you forgot to fill in your system specifications.