96 taurus wont go/stay in park

My g/friends taurus wont stay in park, and I am having a hard time putting it back. i tried a new nuetral park sensor, and also adjusted the shaft or whatever going to it. i can manually put it into park under the hood, but not anything else.
I dont know what is wrong.

today she went to put it in park, the car started rolling after she got out and locked the doors, pretty funny i know, but it sucks for me, i have to fix it. and im 200 miles away.

anyway any suggestoins would be great.
thanks
Joe

Adjust the linkage and tell her to use the emergency parking brake every time she gets out until you do. If you can adjust it in to park under the hood it's probally just a linkage problem. Get yourself an Hays automotive manuel at any autozone or parts store of choice and it will run you through the details. Manuel 15 dollars, admiration of your girlrfriend: priceless.