IMac no bootable device -- insert bootable disk?

Question

i keep getting this message everytime i start my iMac. i reboot and hold option and i get nothing... my iMac cant recognize my hard drive... is my hard drive dead? how can i fix this please help..my imac only recognizes disks. i had a ubuntu live cd and i tried to install ubuntu but then i got some kind of error then i rebooted and mac osx was no longer available to boot..neither ubuntu live cd can see my hard drive or nothing please help me.

Answer 1

command + option + P +R worked right after restart when this happens to me. now verifying my he'd