thanks Cold, I did force start holding option and my Mac HD is fine, everything seems ok, couple questions:
1) That black screen with: "can't find bootable disc"
was that a Mac screen or windows thing?
2) I have a perfect clone on an external, how come that bootable OS would not even come up? Does the computer "see" the HD clone external in these types of situations?
3) I was able to post this on my lapop in the other room. But curious, if my primary computer, the imac, which is plugged into the router, how did the laptop work just fine -- internet etc? if the imac was having a meltdown?