wireless keyboard stopped connecting. Tried all remedies on forum, nothing worked. Keyboard blinks green, but not discovered by iMac.

Wireless keyboard stopped connecting to iMac. Replaced batteries, restarted computer. Keyboard blinks green- cannot get steady green light. Computer does not recognize keyboard, nor connect. Tried deleting device and re-connecting, but keyboard is never seen by the Mac. Also tried same keyboard with a Macbook Air and keyboard was not recognized. other bluetooth device (mouse) works fine. Ideas?