Internet Explorer has long been known to be a very temperamental browser. Settings seemingly get changed without user intervention and it is very hard, if not impossible, to know what settings to tweak to restore original behavior. Given this, it is often easier to reset the browser than waste time trying to find a mystery-setting.
Resetting Internet Explorer
While logged into the computer, open up Internet Explorer. Click on the gear icon, click Internet options, select the advanced tab, click Reset, select "Delete personal settings" and click Reset.
Once the reset is done, you'll need restart the browser by closing out of Internet Explorer and then opening it back up.
Turn on Proxy Server for Internet Filtering
If you are using a netbook that has Internet filtering/blocking turned on, you'll need to reapply the block. Go back to Internet options, click on the Connections tab, click "LAN settings" and make sure the proxy server box is checked. In the event that the netbook uses K-9 Web Protection, you can skip this step.
If you have any questions, please contact firstname.lastname@example.org.