Wireless keyboard turns on but can not type. Can not do any of the trouble shooting I read about because I can not type my password .... Please Help

The Apple wireless keyboard will not work. Batteries are new, light is on & goes into search mode. Worked fine yesterday, today - wont type. Can not do any of the troubleshooting I read about online because I can not type my login. Is there a lock key I may have hit by accident and can unlock? The bluetooth is working because my wireless mouse works...Please Help