The front-man was pencilled in for a switch to Port Vale as part of a deal to bring Leon Constantine to Oakwell but the move collapsed.
And it was left to Richards to punish QPR's sloppy defending and plunder his sixth goal of the season ramming home a shot from six yards seconds before half-time after Martin Devaney and Brian Howard linked cleverly to set up the chance.
In a grim tussle neither side produced a convincing chance on target in this dreary basement scrap until Richards finally broke the deadlock. And, after a second-half fightback from QPR Brian Howard added the second with a lob from 20 yards.
Howard, Barnsley's star performer, engineered an early chance for the Yorkshire side when he whipped in a curling free-kick for Richards but his glancing header was blocked by the towering frame of Damion Stewart.
Richards triggered a burst down the right from Devaney with a pinpoint angled pass but the resulting ball into the area was hustled clear.
But at the other end, when Steve Lomas prodded a hasty shot, he hit Paul Reid and it fell kindly for keeper Nick Colgan.
And when Howard's astute pass sent in Richards the striker shot straight at the keeper with the goal at his mercy before his blushes were spared by an offside flag.
At the other end a Lomas shot hit Paul Reid and dropped into Colgan's arms and when the ball fell for Jimmy Smith his shot screwed wide of the target.
Paul Furlong headed down a dangerous cross and Smith saw his close-range effort break off Reid and when Stewart headed down it was cleared by Colgan's feet before Richards grabbed his goal.
Five minutes into the second half a cross from Lee Cook was perfect for Furlong waiting at the far post to nod in an equaliser but Adam Eckerlsey reached it and made a vital header.
Ten minutes into the second half revitalised QPR were hunting for a leveller and almost found it when Cook swung in a testing free-kick but Dexter Blackstock's header was well held by Colgan.