cam chain problem 2.2 petrol 2002 ???

hello everyone,I tried to start my car this morning it did start but was running very rough, so i decided to check my plugs,after cleaning them i tried again no joy woulnot start at all i also noticed the bottom pully was not turning am i right in thinking this could be that my cam chain may have snapped its a Vauxhall vectra 2.2 i would be greatful of any advice thankyou Nick.