Hi sandyb7,
Thanks for visiting Apple Support Communities.
Be sure to try these steps from the article above (Troubleshooting wireless mouse and keyboard issues) if your keyboard is not responding:
- Push and release the On/Off switch to turn on the Apple Wireless Keyboard.
- When your keyboard is on and paired, and the batteries are charged, the light will glow steadily for several seconds, then turn off.
- If your wireless keyboard isn’t paired with your Mac, the indicator light will begin to blink. This indicates your keyboard is in discovery mode and ready to pair with your Mac.
- If the LED doesn't light up, remove the batteries to make sure they're good and that they're installed correctly.
If your keyboard is not pairing, or is paired but is not responding, next reset the SMC on your iMac using the steps in this article:
Intel-based Macs: Resetting the System Management Controller (SMC)
http://support.apple.com/kb/HT3964
Best,
Jeremy