Auto trans will not go into park or wont stay in park any ideas

When you move the selector to park, does the selector feel like it doesn't move all the way to park?

 

Does the selector pop out of the park position?

 

Or, when you move the selector to park and take your foot off the brake, the car still rolls?

is the button on the shifter working properly?

broken front axle?

 

PLEASE tell us the model, year and mileage of the vehicle. also, any wrecks or work done recently, general condition of the vehicle, etc.