Macbook Pro keyboard not working

I has shut down my Macbook Pro and packed it for travel. Upon arriving at the destination, I booted the laptop. On the login in screen. I was typing my login information but nothing was being entered. The cursor can be moved by the trackpad but pressing the shutdown, sleep, or other buttons on the login screen does not give a response. All I could do was hardreboot. Here's what I have tried so far:

Pressing the option button 5 timesk, and retrying the keys.

When booting up, pressing the D button and running both the short and extended diagnostic test. They found everything to be normal.

Booting into Safe mode. The keyboard still was not able to enter login info at the safe boot login screen.

I tried plugging in a usb keyboard but I got a prompt that said: In order to install the USB keyboard, press continue. But I was unable to press this button using the cursor or hitting enter because neither responds.

It's just strange because I know that it's working at some level otherwise it wouldn't have recognized the D, I pressed and gotten me into the Diagnostics tests. Why doens't it work at the login screen? Any ideas? I really appreciate the help because the computer is 3 years old and no longer in warranty.

Thanks!