I need to resurface a wall that has a layer of 1/2" drywall with another layer of 1/2" drywall. I intend to use laminating adhesive and type g gypsum screws. Do I need to be concerned about getting these screws into the studs or just screw drywall to drywall?

Studs. You're not going to find a screw that will bite into drywall enough to squeeze the adhesive and hold the panel up.

Is there a reason that you don't want to remove the existing drywall, aside from just not wanting to do it?

I find it preferable to pull the drywall and reskin than to build out all of the doors, windows, outlets and switches.

Thanks,
Json

Floofybunny - Yes put at least 4 or 5 screws to the stud , before you start the new sheetrock ,find the centers on a few studs at the top and bottom, and lighty mark ceiling and floor, use a rule or tape measure and mark stud centers on 16 inch centers,After laying out is done then start your sheetrock, ;;; Hope this helps you out ,If it does rate my answer below :::: good luck & GOD BLESS :::F>B.E.