The cold restart process is a technique first used by Chief Engineer Montgomery Scott in 2266 on board the USS Enterprise. It consists by manually combining matter and antimatter, causing a reaction and forcing the activation of the warp engines in a second, instead of power the engines previously and them activating.
After discovering the intoxication of the water that killed the Science Group of the Federation at Psi 2000 and beaming over back to the ship, the Lieutenant Joe Tormolen, that was intoxicated, unwittingly spread the polywater molecule, and Lieutenant Kevin Riley, affected by the polywater, shutdown the engines, diving the Enterprise out of orbit and in direction of the planet.
Scotty knocked Riley down and, via manual matter-antimatter combination, powered and activated the warp engines, saving the Enterprise. But the extremely high speed, along with the gravitational field of the planet, broke the space-time continuum and sent the ship 3 days into the past. (TOS: "The Naked Time")