Surround sound seems to have uninstalled itself

To see my PC specs, see this thread: http://forums.majorgeeks.com/showthread.php?t=67822

Now, one day I change my installation of Microsoft Office, towards my debugging of my gaming troubles; specifically, I get rid of CiceroUIWndFrame, as it appeared at the top of a Counter-Strike crash, and several Internet sources said it was unnecessary. I reboot my computer, look at the bottom-right, and notice that the icon that tells me my 5.1 surround sound is running is not there. Sure enough, when I play a song in WMP, my centre and rear speakers and sub-woofer are not working, despite the fact that everything is plugged in. I do a little searching on my computer, and nothing will admit that surround sound is installed. Normal 2-speaker sound still works for all programs, mind you; which is strange, since all my sound is still being routed through the signal splitter that attaches to my 6 speakers.

In desperation I go to Add/Remove Programs and click on the Change/Remove button for the surround sound. To my horror, it uninstalls it all before asking me if I wanted to! Having no clue what to do, my computer is eventually shut off and turned on again, and it's telling me new hardware has been detected. It seems to install nonexistent drivers, and says it's finished, yet my surround sound still doesn't work. There's still no icon in the bottom-right telling me a surround sound process is running.

I don't even know where to begin debugging this problem. Note that I don't even know if the alteration of Microsoft Office has anything to do with it, I include it only because my surround sound disappearing and my changes happened to coincide. Only after the sound disappeared did I realise how much more I liked songs like Smells Like Teen Spirit with the bass up.