I can't connect my wireless keyboard at work to the iMac. It was connected before, ran out of batters, swapped batteries out and now it wont pair. It's discoverable and shows up on bluetooth setup but when it's time to enter the passcode, nothing happens when I'm typing on the keyboard. Currently using a regular usb connected Microsoft keyboard to type. Magic mouse is able to connect fine. Tried restarting and updating Bluetooth firmware, but none of that fixes the problem. Any suggestions? Thanks in advanced!