So, you've installed Firefox on your PC and you don't use Internet Explorer anymore except to run Windows Update... but what if someone comes along and sits down at your computer and, not knowing any better, runs IE to visit some website? That's right, your computer could get infected. So how can we prevent those who might be ignorant of this fact from unleashing disaster upon your computer?

"Content Advisor"

First, open the Control Panel (Start -> Settings -> Control Panel) and double click "Internet Options" which will bring up a window.

Click the "General" tab and change the Address in the "Home page" section to http://windowsupdate.microsoft.com

Click the "Content" tab. Click the "Enable" button and input a password that's easy to remember; it doesn't have to be anything complex (something like "wu" works fine :) For the "Hint", use something like:

Internet Explorer is ONLY for installing Windows Update patches; please use Firefox for web surfing.

When the Content Advisor window pops up, click on the "Approved Sites" tab.

Where it says "Allow this Web site:", type * and click "Never",
then type http://*.update.microsoft.com and click "Always".
repeat with "Always" for http://download.windowsupdate.com and https://*.update.microsoft.com

Click OK; the Content Advisor window will close.

Switch to the "Security" tab, click the "Trusted Sites" (green circle with the white checkmark in it) and press the "Sites..." button.

Add http://*.update.microsoft.com, http://download.windowsupdate.com and https://*.update.microsoft.com
Click OK; the Trusted Sites window will close.

Click OK again and the Internet Properties window will close. You're all done!

Internet Explorer is now a Windows Update drone, which is a good thing ;)