Why won't my keyboard work for logging in?

I just upgraded my macbook to Sierra and now I cannot log on to the computer. When it gets to the login screen, my keyboard isn't working and I don't know why. Many of the keys, like "P" and "I", don't work at all, but many keys like "O" do something, although I can't tell whether they are working normally or not because I can't see the password. "H" seems to function as a delete key.

The weird thing is, when I plug in an external keyboard the exact same thing happens. However, if I go to the "Reset Password" screen the external keyboard works perfectly, but it won't let me reset my password because it claims I am not connected to the internet, even when I am.

The left "control" key has been stuck on my laptop for some time, which has not been a problem since I downloaded an app to disable it. This did cause me problems logging in in the past, but an external keyboard fixed it easily. However, the way the keyboard is functioning now seems like a totally different problem.

Is there any way for me to log into the computer?