...I try cranking on it as hard as I can... None of this works.
Anyone have any suggestions? Before I shoot the thing?
Cranking down on it as hard as you can with/without a gasket will likely damage the seating surface.
Bad idea. Be gentle but firm.
There should be a disk-like gasket with a small hole- not a built in one. You probably lost it when you removed the regulator. Try looking on the floor in the area you removed the regulator.
have stuck to the previous keg's seating surface. If you can't find it call/go to where you swapped and maybe they'll give you one.