Heh, no worries. This should be an easy fix.
Start up Internet Explorer (6.0 if possible). Go to Tools >> Manage Add-ons... In the show box (near the top in 6.0), select: Add-ons that have been used by Internet Explorer. Find that stmain add-on, select it, then click on the Disable. Press OK and restart Internet Explorer.
That should do it, however, if something needs stmain to run properly, you might experience some more problems... If so, we can work on those as well.