RE: NO CONNECTION FROM KEYBOARD TO COMPUTER (after changing the batteries, green light on indicated)
This has been an ongoing issue for most people and unfortunately it happened to me. I made an appt with the apple "genius" and went to the apple store with my aluminum keyboard and tested it. My keyboard worked. So I went back to work and tried what the apple "genius" told me to do but nothing helped. He actually told me to turn the Bluetooth Off but I forgot that it would be completely impossible because my mouse would lose its connection...the genius should have told me in case you have a wireless mouse then there is another option, but the "genius" didn't. Go figure.
Apple self help guides you through all the steps to fix technical problems and usually most work, that is if you are patiently reading through all the steps, or not easily frustrated. I did all the necessary steps but again nothing helped.
I figured the only thing I didn't do was sort of "reboot" the keyboard, by taking out the batteries and start all over again. Sure enough after placing the batteries back in, the computer immediately recognized my keyboard. Again, go figure.
RE: NO CONNECTION FROM KEYBOARD TO COMPUTER --- DURING LOG IN (after changing the batteries, green light on indicated - solid light for a couple of seconds, blinks twice after)
NO SOLUTION. Purchase or use an old keyboard that connects to your computer with a USB to log in and type your password then proceed to the necessary troubleshooting.
Good luck.