Where do you enter the passcode for wireless keyboard?

I received Macbook 2.1 as a gift. The former owner and I reinstalled Snow Leopard and I entered my personal information as part of the installation. When I used the bluetooth assistant it recognized the Mighty Mouse right away and used my name for the mouse - it works great.

When I tried to do the same for the keyboard the keyboard showed up as the previous owner's keyboard. It wouldn't delete. I said go aheaad and use this keyboard. A passcode appears in a popup and says to enter it when the keyboard is ready. But nothing ever appeared for me to type the passcode in. Finally the box with the yellow triangle said unable to complete pairing process. I've tried this a few other times,, same problem.

I have done the updates and nothing helps. I even used the mouse and keyboard cd which installed Ruby - and no luck. I can't understand why the keyboard shows up as the other person's since they are gone from the system..

I even used a terminal window with sudo to do a find -depth and grepped for files with the other person's name and there are none

I appreciate any help. Thank you.