Hi:
On a Ford product built in the last ten or twelve years, you have something called a transmission range sensor that takes the place of the neutral safety switch of bygone days. They go out, and you have the kind of difficulty you describe, plus maybe some others.
When a TR sensor goes out, it can affect other stuff on the car until its fixed, because the stoopits at Ford routed a lot of other electrical stuff through the TR sensor and what is called the GEM module. Power windows may not work, turn signals may not work, other lights in the car may not work. You may also experience a lack of power steering, since some Fords use two electric stepper motors on the power steering rack. You can still steer the car- it just takes more effort.
The fix is actually pretty simple. Any good mechanic or dealer can replace the TR sensor and adjust it for proper function. One "been there, done that" tip: get a gen-yoo-wine Ford part, not a generic one from the local auto parts store. Ford has upgraded the part for better reliability. The repair is in the $125-150 range on most vehicles.
If you have more issues with the car, I suggest using the forums at flatratetech.com and asking the guys there. They're Ford dealership mechanics who help with tech issues on their personal time. Nice bunch of guys.