Why no Service Pack? They are crucial to help solve security vulnerabilities.

What is the error message you get when IE is 'not browsing'?

Check IE's Add-ons, (Tools > Manage Add-ons), and see if there are any suspicious ones that need disabling.

In IE > Tools > Internet options, then the Connections tab, click the "LAN settings" button and make sure there are no Proxy settings. If there is anything there, remove them all.