McGovern produced a moment of magic against his old club to put Swindon ahead four minutes before the break, lobbing Willy Gueret from a long way out.
The Dons burst out of the blocks after the interval and Easter opened his account to equalise with a cool 53rd-minute penalty, after Lewis Gobern had been tripped in the box by Lescinel Jean-Francois. But Swindon restored their lead just three minutes later as Paynter's deflected left-foot shot from the edge of the box flew into the corner of the net.
Paynter completed his brace to make it 3-1 in the 71st minute, poking the ball home from a yard after the jittery Gueret had dropped Anthony McNamee's routine cross.
And McCracken's own goal three minutes later sealed the rout as he headed Lloyd Macklin's dangerous cross past Gueret under pressure from Paynter.