it has Ask Toolbar in its installer and it might be the reason you're seeing the issue with IE. Ask Toolbar will change your search bar search engine and homepage. And it will add add-ons for IE which will change the way IE runs in some way. The said toolbar is not required to use the application, Stopzilla.
Good thing is you did not have issue removing the offending software and get your IE working properly again.
If you are using Windows 7 beware of Stopzilla. I don't know; maybe I did something stupid. Here's what happened to me.I downloaded Stopzilla and proceeded to purchase and use it. Everything was fine as far as scans,popup blocking etc.Then I noticed that if I clicked on a link within a site,Hell froze over before I got to where I wanted to go.Many items on my favorites list did the same thing. Anyone else have the same problem? Anyway I uninstalled Stopzilla,kissed my $9.95 away and went to Adaware,which I'd used in the past and never had any problems.