I cant get my IMAC to boot up

I moved my I MAC to a new house and it wont boot up. When I first powered it on, the status bar would freeze about 3/4th of the way, then the power would shut off. I tried to restart while holding down command R, command-option-R-H, and a few others with no success. I think tried again with command R and got a revolving globe image and it asked me to input my internet code. Since then, its been powered on, white screen, and I have a screen message with the Globe not spinning, and a large triangle with an exclamation mark inside it, with the text below of apple.com/support. -21 06F. any ideas what do to next?