I had this problem - I solved it by deleting my account and then making a new account using another account. This problem usually occurs if you set the keybord language option at Windows setup to United States. This is a very long way to go about the problem, but I couldn't find out how to do it any other way. If you decide to delete the account, obviously make sure you have access to another account and choose the Keep Files option when creating your new account. I'd always back up my files before doing this just in case!
Genius1 may be right, but I would change the setting to English United States, reboot and test that. Then change the setting back to English United Kingdom, reboot and let us know the result. If that doesn't work I would try a system file scan.