From your description, although you saw the Microsoft Windows Update icon in the Notification Area, (often called the System Tray), it seems the sound stopped working before you installed the update. That makes me think this was just a coincidence.
Which Windows, XP, Vista, Win 7?
Can you just check the Taskbar properties? Right click the Taskbar, select Properties. Look for the "Notification area" tab, then something like "Hide inactive icons". Click the Customize button and search down the list to see if the Volume icon is there. Or just below that button, (at least in my Vista), whether Volume is ticked in the System icons section.
Even if it is ticked, untick it, click Apply/OK, then return and tick it.
See if that works.
Mark
After having been on the computer most of the morning with no problems, I tried to play a video and received an error message that there was no sound device intalled or the sound device was not working properly. I got offline and tried to play one of the songs in my Windows Media Player Library--I received the same message. In addition, the volume control icon was no longer in the task tray. I restarted the computer, but received the same message--still no sound.
I had noticed earlier that there was a Microsoft update icon in the tray, but I had not yet installed the update. Although I have received automatic updates from Microsoft for years, on at least two occasions over the last month, the update icon has appeared in the tray. I thought this was unusual, but installed the updates anyway.
Today, after restarting the computer did not correct the sound problem, I installed the Microsoft update, which then required that I restart the computer again. When I restarted after installing the update, the sound was fine. The volume icon, however, was not in the tray--I tried to add the icon to the tray, but it still does not appear.
Is there any way that the sound device problem is somehow connected to installation of the Microsoft update? I have never had this problem before, and wondered if there's something I should know in case I encounter a similar problem in the future.
Even though it appears as if there is no problem with the sound device, it seems to me that something happened and the only "uncommon" denominator, so to speak, was the notification of and installation of a Microsoft update that was not automatic.
I would appreciate any feedback you think might be relevant. Thanks a lot.
SlimShadie56
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic