Currently Being ModeratedMay 12, 2013 8:09 PM (in response to jrmorse)
It's trying to boot from a network server, most likely Internet Recovery. Hold down the option key at the startup chime to bring up the Startup Manager. You should see all available local boot volumes. Choose your usual boot volume ("Macintosh HD," unless you gave it a different name) if it's shown. Otherwise the next step depends on your backup status.