Check this,display the volume icon in the taskbar notification area, you must select the "Place volume icon in the taskbar" check box in Control Panel Sounds and Audio Devices applet.
I have been trying to figure out how to get back my volume control the past few days. I listen to audio alot while reading my emails, etc. so it's driving me crazy! It happened when I went to the Windows ME updates page, and it downloaded a bunch of programs, such as Notepad, Drivespeed, and High Color to name a few. After I went to the volume button on the bottom of the screen, it was gone! I'm thinking I have to erase a program to get it back up, but am not sure... Is there anyone out there who knows what to do in this situation? Any tips? Any will be greatly appreciated. Thanks.