If you are unable to change Internet Explorer search provider using the normal way of tools-manage addons I'm posting this solution in case anyone searches for it. For anyone using IE11 who can't add Google (or any other search engine to IE)here's the way to fix it.
Go to another machine running IE11 (it would be best if that machine is running the same OS as you but in my case my problem was in Windows 8.1 and my other machine is Windows 10 Technical Preview.)
On OTHER computer add whatever search provider you want to IE using tools-manage addons
Go to regedit-HKCU\Software\Microsoft\Internet Explorer\
highlight "searchscopes" and export the key to a file by clicking file-export-save file as searchscopes_good.reg
close regedit
Copy the .reg file you just exported to a flash drive.
(Don't forget to remove whatever search provider you added to this OTHER computer.)
Go to PROBLEM computer. To be safe make a system restore point.
Open regedit and navigate to HKCU\Software\Microsoft\Internet Explorer\.
Export the key "searchscopes" to a file and name it searchscopes_old.reg
Put the flash drive in and right click on the searchscopes_good.reg file-select "merge"
You can now use tools-manage addons to set your default search provider. If it doesn't work just go to wherever you saved the searchscopes_old.reg-right click and merge.
Hope this keeps someone else from spending hours on this problem like I did. No matter what I did I could not change my search from that danged Bing.
