The first thing to try if you haven't already, is your restore points prior to this and had you downloaded anything immediately before ?
I assume you will have reset IE to defaults but have you also gone into Tools - Internet options - Connections - LAN settings and ensured that the Proxy server box is unchecked and just the top one is ?
Have you tried running IE as an administrator ?
Have you tried turning IE 11 off and then on after a reboot in Programs and Features/Turn Windows features on or off ?
It's best to have another browser installed before you do this.
Do you have any problems when using another browser ?
Do you get the same problem when booted up into Safe Mode with Networking ?
If not then see if you get the same problem with a clean boot
http://support.microsoft.com/kb/929135/en-gbIf it doesn't occur in Safe Mode with Networking but does occur in a clean boot then that would point to your AV program - else one of your Startup items or non MS services.
Anvi Browser Repair Tool can be an effective tool to resolve browser problems.
http://download.cnet.com/Anvi-Browser-Repair-Tool/3000-18512_4-75835298.htmlYou can view what it will reset by clicking on the relevant icon in the left pane, but I just leave it at default settings although I have to reinstate my TalkTalk home page afterwards.
If the problem occurs in other browsers as well then open a command prompt as an admin by going Start > type cmd.exe > right click on cmd and select Run as administrator > accept the UAC and enter -
netsh winsock reset catalog
ipconfig /flushdns
ipconfig /registerdns
exit
Then reboot.
If it still isn't resolved after that then run a sfc /scannow command from an admin command prompt and see what that reports.
I would also expect to see something recorded in Event Viewer.