I have the same problem. Function keys work, but none of the letters or numbers work, so I can't log in in hte appropriate field. I can move the icon with the mouse, (bluetooth or USB) I've tried 2 keyboards, one USB the other Bluetooth, but I can't get past the log in screen cos the letters & numbers don't respond. I can adjust the brightness using F1 & F2, and I can adjust the volume with F11 & F12.
Luckily I have this MacBook Air!
It started off as a hardware issue where I couldn't even start up. Also I can't get a hardware test to run to completion (you know, switch on whilst pressing D). Strange that the D key works for this!
Any ideas anyone?
I had a similar problem and none of the suggested troubleshooting techniques worked. I had been using the calculator widget and suddenly none of the number or function (addition, multiplication, subtraction, division, clear, etc.) keys worked. Finally, I had to go into the Manage Widgets and delete the calculator and add another one. That solved the problem.
It wasn't an accessibility problem and there was no issue with the number lock key(s). Just some weird sudden software glitch.