@RodAtWork: Does it just keep on loading (and presumably time out at some point)? Or is the content somehow not displaying? Have you checked whether it's installed any addons into IE?

Have you tried Windows' built in "Diagnose and Repair" feature?

You could try resetting Winsock and your TCP/IP stack. (Instructions here: http://www.mydigitallife.info/reinstall-and-reset-tcpip-internet-protocol-in-windows-vista-2003-and-xp/ http://www.mydigitallife.info/repair-and-reset-windows-vista-tcpip-winsock-catalog-corruption/). (Although it's intriguing that your computer still appears to be connected to the internet... the above website also suggests turning protected mode off.)

Finally can you download another browser on another PC and transfer it via flash drive and see if that works?

Also what happens if you try a tracert or ping? Does the event log give you any clues?