The Yellow Years
After losing the power ring the Guardians had given him, Guy still wanted a source of power. He tricked Lobo and a bunch of neive Green Lanterns into taking him to the tomb of Sinestro, the rogue Green Lantern. After many battles on his way there, he fought in a mental battle against the spirit of Sinestro. He won, and went back to Earth.
After returning to Earth, Guy started fighting everything from intergalactic mercenaries to crimelords, on his sort of " one man campaign against scum ". He also formed a group called the Gardners of the Galaxy, in sort of a parody to Marvel's Guardians of The Galaxy. He ran this group for about 10 issues, than stopped after paying his debt off with Lobo from his help in getting the yellow power ring. These were the good days.
Here it is. The saddest, or one of the saddest things that has happened to Guy(the others being the death of Arisia and Ice).Hal Jordan, the most highly revered GL, had his hometown, Coast City, destroyed by Mongul and the Cyborg during the whole Reign of the Supermen thing. It was basically the equivalent of Superman's Metropolis to Hal. He was fine for a while, but then started to want to ressurect the whole city and all of it's people. He did, for about 24 hours ( the time limit on a GL's ring until it has to be recharged again ) and was "bonding" with his dad, who he didn't know all that well, when the charge expired. A Guardian appeared an demanded that Hal turn in his ring for using it for personal gain. He drained the Guardians power ( rather, it's projection, it was a hologram ) and got enough power to go to Oa, the GLC's home base, essentially. At this point, Hal went nuts. He went to Oa, slaughtering GL's that had been put there in his way to stop him. He defeated of killed every one of them, and reached the main power battery. He was about to consume all the power for himself when the Guardians ressurected Sinestro and gave him a power ring. He and Jordan battled, and Jordan snapped his neck. He conumed all of the power, and all of the Guardians died, except for Ganthet, who was given all of their energies. So, while Guy was fighting the bad dude Militia, who was actually his brother, Mace, his yellow ring fluctuated several times, turning off and on over and over again. He finally defeated Militia, and Green Lantern Alan Scott appeared to tell him that Hal had lost his marbles, and that was why his ring had fluctuated. So, Guy, Arisia ( a former GL and one of Guy's love interests ), Wonder Woman, The Ray, and J'onn J'onzz, the Manhunter from Mars, whnt into space to try and defeat Hal. Hal beat them all, and absorbed Guy's power ring. So the Yellow Years came to a close.