I get from Dell new XPS 420 desktop with installed Windows Vista Home Premium an on board sound module(SigmaTel HD Audio). When I'm feeding analog audio(came from tape player) to line-in , I don't hear any sound coming from computer speakers. Nothing is muted and indicator in "Recording Audio Devices " box showing that signal is coming into computer. Also I can record this sound but hear no sound during recording. Upgrade to Sound Blaster X-Fi , uninstall on board audio and have same result. Contact Dell tech. support and they cant resolve problem. Any advice , please.