Duh

I have a 1989 mercury topaz

I istalled a new righthand cv joint and the car won`t get into gear not even when I put the car in park its is neutral . I removed a pin and the end of the cv joint could that be the problem?

What do you mean you removed a pin? Did you take something out and not put it back in?
A disconnected CV joint on a 2 wheel drive can spin and a car (the differential actually) will perpetually think it’s going around an infinitely tight corner. So the disconnected axle spins at a high rate while the connected axle (the one getting traction from the tire) doesn’t get the turning power. Result: it acts much like it’s out of gear all the time.
(Unless maybe you have a limited slip differential)

Rob

^^^Just for the sake of argument: Also, I think a 4 wheel drive or all-wheel drive would still go forward, too.

Rob

To avoid such problems as you have encountered, is why maintenance manual, such as HAYNES or CHILTON’S, were made. Tell us that you are using one (the small, model specific one, NOT the Big Book).

Call a reputable shop and have a wrecker deliver the car there.