Thanks for all of the replies. The house is ten years old, so it is
new to us, not new as far as the code requirements for a 4 prong
outlet go. I am not an electrician and do not know anything about the
wiring of the outlet. We just now found the dryer manual and it has a
section of instructions on connecting it to a 3 prong cord. So I am
going to follow those instructions. The instructions show the green
ground wire being left in place attached to the green ground screw on
the case.

Thanks for your help and comments.

Robert