Sex Factory was the name of a band that Mike Nelson was working with back in the early '80s. He put his temp work ahead of his band, eventually working for Dr. Forrester. By that time, however, the band had most likely dissolved.
Inspired by the movie Time Chasers, Crow decided to go back in time to convince Mike not to take temp jobs that would land him in space. At the time, Mike was "tempin'" at a cheese factory. The name 'Sex Factory' disgusted Crow, but nevertheless he convinced Mike to pursue the band instead.
The band did remarkably well, opening for Motorhead (who made their singing debut in the Experiment Zombie Nightmare) at the Cleveland Civics Center. It was the last night of Mike's life in this alternate timeline, as several female fans threw large hotel keys that caught him in the head. He died right on stage. His brother, Eddie Nelson, was truly proud of him and his death that night, saying that it was "an excellent way to go".
After Crow sees this new future, he goes back to convince himself not to convince Mike to pursue the band, and the timeline is restored. For Mike, at least.
Mike's position in the band is unknown, but due to the fact that the girls were throwing the keys at him, he was likely the lead singer and/or guitarist. Mike has been seen singing and playing guitar, at various levels of talent, so both skills are dubious. It is unknown who else was in the band.
It is also unknown if the band continued without Mike in either universes.