Sorry....that's the first thing I tried! (It says the volume control is 'Inactive'
Honestly, and not to sound cliche, but I think it's a driver issue. Can you try an older driver and see if the icon comes back? If yes, then it's a driver issue. If no, then it's possibly something else, (but doesn't mean it's not a driver issue, if for some reason the new driver broke something that would not be fixed by uninstalling) and I would not know where to begin looking as I don't have a soundblaster. You might try a system restore point to before you installed the new driver, if possible. Otherwise, another cliche answer would be to nuke and reload with the new driver to see if that fixes it. Depending on which build of 7 you are...