Tottenham target Reid put Forest in front after 24 minutes with a curling 20-yard free-kick after he had been fouled by Danny Shittu.
And a minute later Reid set up Kris Commons for a fine finish, his first since a £300,000 move from Stoke.
Reid then tapped a free-kick to debutant Yoann Folly, on loan from Southampton, to fire home from 25 yards with eight minutes left.
Nottingham Forest caretaker boss Mick Harford:
"Andy is a top class player.
"We gave him a free role and Gareth Taylor was able to hold the ball up well and bring him into the game.
"Obviously you want to keep your best players but it is down to the chairman and I don't know what the situation is - I get asked that every day."
QPR: Day, Branco (Thorpe 76), Shittu, Edghill, McLeod,Ainsworth, Bean, Rowlands, Cook (Padula 76), Gallen, Cureton.
Subs Not Used: Cole, Mulholland, Townsend.
Nottm Forest: Gerrard, Louis-Jean, Dawson, Morgan, Doig,Commons, Folly, Bopp (Perch 80), Robertson, Reid, Taylor.
Subs Not Used: Doyle, Johnson, Impey, Harris.
Booked: Bopp, Dawson.
Goals: Reid 24, Commons 25, Folly 82.
Ref: M Atkinson (W Yorkshire).