Hello and thank you for contacting us, a paid expert support site. My name is XXXXX XXXXX I'd be glad to assist you with your issue.
As I understand it, you are being asked for a login but you are unable to type, is that correct?
Ok, is your keyboard wireless?
Ok, if you press the caps lock key, do you see a light show up anywhere on the keyboard?
Ok, you might need new batteries, then. What type of keyboard is it? Logitech? Microsoft?
Ok, do you have any replacement batteries you can put in there?
Ok, we'll need to try that first to make sure that it was just the batteries. Is that something you can do soon (get the batteries) or would you like to check back in with me later?
Ok, sounds good. I will be on around 9am eastern (about 12 hours from now).
If this an imac?