How to Uninstall IE7:
  • 1. Go to Control Panel
    2. Click Add or Remove Programs
    3. Click Show Updates checkbox
    4. Click whatever version of IE7 you have. For example "Internet Explorer 7 Beta 2 Preview"
    5. Click the Change/Remove button
After you uninstall Internet Explorer 7, double-click the Internet Explorer icon to verify that Internet Explorer 6 is restored

I TOO use Firefox. It is my default browser. I only use IE6 to download any updates which require using IE6, these generally are just the Windows updates.