HELP! blank screen with squares after I erased the disk!

My iMac was running very slow so I was advised to erase all settings and data as you can from the settings. once I did this this screen appeared as since I have not been able to login or do anything. Please help!

the squares read: 'BootKicker.efl', 'OpenShell.efl' and 'Reset NVRAM'

Please HELP!!