IE Restorator fixes common Internet Explorer problems
IE Restorator can reset Internet Explorer to its default settings, re-register both 32 and 64-bit version of IE, and perform Winsock resets and flush the DNS cache.
It's also totally portable and makes an excellent addition to your flash drive or network share. As both a technician and "the friend who knows computers," I've had to perform these actions manually more times than I care to count. Restorator makes them as easy as clicking a button -- just make sure you right-click and run as administrator to avoid any permission issues.
Looking for something like this but with more features? Have a look at previously-reviewed RepairIE.