Hales, back in the side for the first time since breaking his hand during the tour of India earlier this year, was the star performer with 110 runs off 107 balls to mark his return to international cricket in style.
Fellow opener Jason Roy managed just 17 runs before he was dismissed, but that brought Root to the crease and his partnership with Hales quickly put England in the driving seat.
Root then went for 101 before the Windies began to tear through the England tail, with only Ben Stokes (34) putting up any notable resistance in the final few overs.
However, the partnership of Root and Hales had already done the damage, and England made a perfect start with the ball as they took three wickets in the first four overs to leave West Indies 13-3.
The hosts' wickets continued to fall with alarming regularity, leaving them 87-8 at one stage until Jonathan Carter made things a little less embarrassing.
Carter's stand of 46 was the only notable resistance to England's dominance, though, as the West Indies were eventually bowled all out for just 142 with more than 10 overs remaining.