It seems it will take more than a computer shutdown to end the career of NASA's pluckiest rover. After a scary communications breakdown, contact with Opportunity has been reestablished and normal operation has been resumed. NASA posted an update on their website reporting:
NASA's Mars Exploration Rover Project received confirmation from Mars this morning (May 1) that the Opportunity rover is back under ground control, executing a sequence of commands sent by the rover team. Opportunity is no longer in standby automode and has resumed normal operations.
No word has been released as to the cause of the shutdown.