Remove the cover cover, remove th emotor for the sunroof, and use some pliers to manuall close it turning th egear. SOunds like the plastic gear is tripped. Happened to me yesterday,

2006 Pontiac G6 3900SFI GTP Coupe CAI, Stainless Cat Back, Vector Tune, Strut Brace, Eibach Pro Kit, Custom Made Projector Headlights, 4300K, 20% Tint Former Owner- 2000 "Stryped" CSVT CEG Dragon Run- Oct 13-15