Get Fx 0.9, make it the default browser, then...
1. Get Firesomething extension for Firefox 0.9
2. In the dialog box, remove "Mozilla" vendor and add "Microsoft". Remove all prefixes also and add "Internet". Remove all names and add "_Explorer" (substitute the underline for a leading space). Enable the "single name mode". Apply.
3. While you are at it, get the Luna Blue 0.4 theme from http://www.intraplanar.net/projects/lunablue/
4. Adjust the icons so they look really like explorer. The order should be back, forward, STOP, RELOAD, home, separator, favourites, history, separator, mail, print
5. Do as stated above, rename the shortcut to "Internet Explorer" and change the icon to the blue "e"
6. Never again worry about worms.