Disabling IE will produce no benefits in security vulnerability nor system performance. Almost every program that auto updates along with w7 updates uses IE or the IE engine and functions. Just leave it and don't use if you don't want to. :)
First thing I do as well is disable IE before setting up my internet drivers. Have never ran into a problem where program says needs IE. If I ever do i'll find a different program. In malwarebytes under more tools click on one of those links. It will bring up IE even though default is firefox. Don't have IE any more so cant confirm but when I was going through this you couldn't change the defaults for certain extensions from IE like .url. Even changing them in Control Panel\Programs\Default Programs\Set Associations didn't (still don't for firefox) work for me so bye bye it went. IE used to be a highway of virus. Not sure how it is now but I don't care to ever find out. Not only that but you got constant updates to instal. No good reason to keep it.
What a lot of programs need to work is a default browser. IE is just one of the bunch.
Still it is nowhere near the mess that IE 6-7 was, (it's actually pretty secure, more than a standard firefox).
I still need it because some of the sites I go on are still "optimized for Interent Explorer".
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