One more way to fix this (at least in vista).
1. Go to network and sharing center.
2. At the bottom look for "Show me all the files and folders I am sharing" and click it.
At this point your pc will compile the data and show all files and folders. Once this happens you....
3. Click to highlight a Folder or File.
4. Press Control and A (Highlights everything).
5. Right click over highlighted folders and files.
6. Look for Share in the menu and click it.
7. Click on stop sharing.
This gets rid of the sharing icon.
If your sharing folders and files, this might not help. But if you don't share anything like me, it should work fine.
Shane sorry I'm late on this
. I meant to post it earlier
Chris