Windows Navigation Sounds

Hey guys. I was just browsing the net trying to find the solution to an audio problem I have and I ran into this guy with a similar problem:
http://forums.majorgeeks.com/showthread.php?t=142308

I thought you guys might be able to help --
Basically, my Windows Navigation Start.wav is not playing when I click on links in IE. It was playing, then I had temporarily set it to None, and when I set it back, it no longer plays.

I followed the steps in the above post, but none of them have resolved the issue. I've checked to make sure the associated sound has been set, and it has. In fact, within Windows Explorer, the sound will play fine -- just not in IE. Would anyone be able to help? Thanks!