I think theres an option to uninstall IE. Control Panel --->
Add remove program ---> Windows component tag
Uncheck IE and click ok.
However, thought I also hate the fact that some MS applications
just open up IE even though I want FF, I think keeping IE is good.
Not that IE itself is good, but just that sometimes some website
can have problems with FF. This used to be often last times, but
now FF is getting a bigger and bigger coverage. Still just keep IE
for backup