How come the international keyboard on my Toshiba stopped being international?

Q: I have a Toshiba Satellite laptop with Windows 7. I had been using the United States International keyboard option but it has stopped working. The keys like the ‘quote mark and the tilde ~ print twice instead of combining with the next character. I have tried reinstalling the keyboard option but I still have the same problem. I am not sure when it started so I cannot link it to a particular update of Windows but I haven’t made any changes to my hardware nor installed any new programs. I am using the Microsoft Essential anti virus.