Click on Start, Settings, and Control Panel. In side of the control panel window, click on Sounds And Audio Devices, or the eqivelent. In this utility should be a place to put a check mark that will allow the volume control icon to appear in the lower right tool bar.
I am running Windows 98SE on a Pentium II 300 machine. I have been using the computer to play MP3 files successfully for some time now. All of sudden, one day my volume control Icon disappeared from my task bar and I was no longer able to get ANY sound out of the computer. I brought up the volume controls from control panel but those all appear ok, in other words I haven't inadvertantly muted anything. I have not added or taken out any new hardware and the soundcard is the one that came with the machine. (I also swapped out the speakers but that did nothing) Any ideas?