how can i fix my 2002 mondeo ghia ?

i have a 2002 mondeo ghia automatic and the problem is it wont move when it is in drive. itll only let me move in reverse and 1st gear for so long. then i can no longer move it from then. it wont move in 2nd or drive. the transmisson fluid is full yet it still wont let me drive. does anybody have an answer to help with this problem.