The visitors had considered requesting a postponement of this game after 10 players were struck down by a sickness bug in midweek, and the Staggies failed to lay a glove on the Lions.
Ricki Lamie put Livingston ahead in the 31st minute before Dykes doubled their lead before the break.
Dykes made sure he left with the match ball after scoring twice in a one-sided second half.
The result propelled Livingston up to sixth in the Ladbrokes Premiership.
In the end, County were only forced into three changes for the clash, with Liam Fontaine, Michael Gardyne and Brian Graham all missing out.
But those who did play failed to make any meaningful impact.
Livingston should have taken the lead in the 23rd minute when Steve Lawson's corner landed at the feet of Jon Guthrie inside the six yard box, but the defender could not make any sufficient contact and the ball bounced wide.
Gary Holt's side created the next chance three minutes later but County goalkeeper Nathan Baxter got down to turn Scott Pittman's low shot behind for a corner following a flowing move on the edge of the box.
However, the West Lothian side found the net through Lamie. Alan Lithgow's long throw fell at the feet of Dykes and the forward cut the ball back for Lamie to stroke home from six yards.
County had a chance to level minutes later but Josh Mullin's rising drive from 20 yards was well saved by Matija Sarkic.
Livingston then earned a two-goal cushion four minutes before the break after Dykes fired in his seventh of the season from close range.
The Australian was picked out by a superb pass from Steven Lawless and left Baxter with no chance.
The afternoon got better for the hosts just five minutes after the restart as Dykes notched his second.
Marvin Bartley's low drive was saved by Baxter and after Aymen Souda failed to covert Pittman's cross, Dykes was on hand to slot the loose ball into the net.
Lawless was denied a goal after being set up by Pittman when Callum Morris got back to block his effort on the line.
But there was more to come from the hosts as Dykes grabbed his hat-trick in the 73rd minute when got on the end of Bartley's cross to head past Baxter.