I have built-in sound card. My mobo is DFI Lanparty. When I go to Control Panel, Sounds and Audio Devices, under the Volume tab it says "No Audio Device" When I double click the volume icon in taskbar I get a message saying "There are no active mixer devices available. To install mixer devices, go to Control Panel, click Printers and Other Hardware, and then click Add Hardware. This program will now close." I know I have sound because when my pc starts, I hear that sound but when I play a song in real player for example I get "Cannot oper the audio device.Another application may be using it. More info is available at the RealNetworks Customer Support Website." I re-installed my Realtek sound driver by the way.