Users that log in to Windows cannot initially change the volume level by clicking the speaker icon in the lower right corner of the task bar. Here is the answer/not easy fix from CTS but for now it is what we have to work with:
click Start, type “sound” (without
quotes), and click the Sound app that appears under the heading “Control Panel”
Double-click the default sound device (the one with the green checkmark bubble)
Click the Levels tab
you can change the volume.
Not the best way to do it, but its our only choice at this
point until we get our newest Windows image rolled out.”