"Bluetooth: Not Available" problem created by software update; need help please?

I ran a regular software update as prompted by my iMac to get to 10.6.8, and now have "Bluetooth: Not Available" with squiggly line thru it. I've tried an SMC, updated software to 10.8.4...no availability of my Bluetooth to work the magic mouse, or any ability to access Bluetooth in System Preferences...help please?