Did you try changing the keyboard language like I mentioned 3 posts before yours?

While at the password screen hold down the shift key and click the power icon then hit restart. Keep holding the shift key until it brings you to the more options screen. Click trouble shoot then...

Read my post above yours...

You can revert back to previous windows via recovery options. Also, try checking the keyboard language settings at the password screen when you try typing in your password, the language settings...