Does anyone know if it is possible to change an existing genie garage door opener (screw drive) over to a chain drive without having to purchanse the entire opener? Is there a kit just to change these? Any help is appreciated.

Hi,
Assuming this is the correct forum, I would say no. It would seem to me that it is not something you can do if for no other reason than I would thing that the motor that operates it would have to be on a totally different axis of operation.
I realize that is probably confusing, To explain let me first say that a screw-drive would have the shaft that rotates pointed toward the door so as to rotate the screw shaft. A chain-driven unit would have the shaft at right angles to the door to turn the sprocket that would in turn pull the chain in either direction.
Peace,
Clarke