|I know it is simple, but try restarting the computer, often this is all that is needed.|
Scan the computer with Malwarebytes. If you do not have another browser for the download, use another computer to download and save the file to a flash drive and transfer the file over to that computer to install. While you are at it, consider doing the same for Firefox (or Chrome) so you have a working browser until you get it fixed. When installing Malwarebytes, uncheck the free trial so you get the free version. Malwarebytes will double check for nasties on your system.
Try restarting in Safe Mode and seeing if it will open there. If it does, do a reset of IE from there and many of the associated problems should go away.
You have to be a little bit crazy to keep you from going insane.