I HAVE VIZIO 70 MODEL E701i-A3 TV WAS ON SCREEN WENT BLACK I PRESS A BUTTON ON THE REMOTE AND THE SOUND WENT OFF. AFTER THAT THE TV WOULD NOT RESPOND AT ALL.

Try a hard reset to this set, and check. If it do not help you, contact any service technician.
There are two types of reset to TVs. The first is simple to do; a Hard Reset; and the other is somewhat skilled; is a Factory Reset (System Reset). To make it a hard reset, just unplug the TV from AC mains wall socket, and re-plug it back after 15 minutes or so. If you do this by overnight; will be better. If you want to make it a system reset [Factory Reset]; you have to enter its service mode option, and select the factory reset option. If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Service mode entry, adjust and exit procedure to many popular brand TVs are given. Never forget to exit the service mode, after all adjustments have been done.