Bottom-of-the-table Lions now find themselves three points adrift of nearest rivals AFC Telford United with a worse goal difference and only two games to play.
The hosts, who already had confirmed their play-off place, played like a team brimming with confidence, while rock-bottom Guiseley struggled.
Kidderminster took the lead with under 10 minutes gone, as Caleb Richards put in a good cross and Ashley Hemmings powered in a header to give the hosts the advantage.
A long ball then found Adam Haw who looked well placed, but he wasn’t able to control the ball properly and the chance was gone.
The home side kept going and Geraldo Bajrami was found with a bit of space from a cut back and he made no mistake, doubling Harriers’ lead and ensured they had the more comfortable half-time team talk.
Any hopes of a positive start to the second half for Guiseley quickly evaporated when a penalty was given to Kidderminster for a handball.
Hemmings calmly placed his shot well past Owen Mason and the game was effectively over.
There was an opportunity for Guiseley when a good cross so nearly found Josh Stones, but despite his best efforts to stretch for it, he just couldn’t make contact and the game ended with the visitors being pointless and goalless.
The Lions next host Spennymoor Town tomorrow (kick-off 3pm), knowing defeat could all but seal their relegation to the NPL Premier.
After the match, Guiseley caretaker manager Steve Kittrick said: “The first and last 10 minutes of games is decisive and to concede so early was frustrating. We had a chance that we didn’t take and that can be the difference against good opponents.
“We have two cup finals now and we simply have to get something from Monday to start with.”
Farsley Celtic remain four points above Guiseley in 20th place following their 2-0 home defeat to York City.
Former York boss Russ Wilcox watched his team cause his old employers early problems at the weekend with Jacob Gratton having a chance ruled out for offside.
At the other end, Adam Clayton also cleared a scrambled Mitch Hancock opportunity off the line on the half-hour mark and the breakthrough did not arrive until the 75th minute when Clayton Donaldson netted his 14th goal of the season.
The 38-year-old veteran dribbled his way into the penalty area before chipping over Celts keeper Dave Robson with the ball adjudged to have bounced over the line despite desperate attempts from home defenders to get back and clear.
Substitute Lenell John-Lewis subsequently made the points safe in the 87th minute, making no mistake from 10 yards after excellent pressing by Maziar Kouhyar had seen him win possession in the Farsley box.
Third-bottom Farsley still remain in danger of relegation but only if Guiseley can pick up four points from their final two fixtures.
A victory for the Minstermen against visitors Fylde tomorrow would secure them a play-off spot.
Bradford Park Avenue fought out a fourth successive 0-0 home draw, with Darlington the visitors for the latest stalemate.