Sorry, wasn't thinking--all the fixes listed at the link below. Wasn't sure how long to hold down Shift-Control-Option-Power, so I tried for at least 25 seconds.
http://support.apple.com/kb/HT3964
In some situations, you may need to reset your computer's SMC. Learn how to identify these conditions and reset the SMC.
Note: It is possible that the SMC could encounter an issue that may cause unusual system behavior typically related to the symptoms described below. In some cases, resetting the SMC may be the only correct method to resolve the issue, however, an SMC reset should only be attempted after all other standard troubleshooting has been performed.
Try each of the following steps in this order before you reset the SMC. Test the issue after completing each troubleshooting step to determine if the issue still occurs.
- Press Command + Option + Escape to force quit any application that is not responding.
- Put your Mac to sleep by choosing the Apple () menu from the upper-left menu bar and then choosing Sleep. Wake the computer after it has gone to sleep.
- Restart your Mac by choosing the Apple () menu from the upper-left menu bar and then choosing Restart.
- Shut down your Mac by choosing the Apple () menu from the upper-left menu bar and then choosing Shut Down.
If your Mac appears to be running normally but isn't responding, force the computer to shut down by pressing and holding the power button for 10 seconds. Note: You will lose any unsaved work in any open applications.
For Mac portables experiencing issues related to the MagSafe power adapter and/or battery, try:
- Unplug the MagSafe power adapter from the Mac and the wall power socket for several seconds.
- Shutdown the Mac. Physically remove and re-insert the battery (if it's removable) and startup the Mac.
If the issue is still not resolved after following the troubleshooting items above, an SMC reset may be necessary.
Resetting the SMC on portables with a battery you should not remove on your own
Note: Portable computers that have a battery you should not remove on your own include MacBook Pro (Early 2009) and later, all models of MacBook Air, and MacBook (Late 2009).
- Shut down the computer.
- Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
- On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
- Release all the keys and the power button at the same time.
- Press the power button to turn on the computer.
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.
--thanks for any help you can offer!