Go to Start > Control Panel > Sounds and Audio Devices. Remove checkmark from Mute > click Apply > OK.
Not sure if this will work, but hope it does.
Recently I installed Audigy sound card on my Pentium III 550 MHz, OS is XP. Sound is OK, media player, Power DVD etc are working fine. I have a TV tuner card and a program called TVR installed for watching TV. Ever since Audigy is installed when I turn on the TVR progrm the Line-in on volume control panel gets muted. I de-selected the Mute to enable Line-in. OK, it worked. Every time I restart the PC and if I run TVR I have to de-select the Mute button again. Pleae help me to resolve this problem. Thanks, Eapen