If there are 2 holes on each side, then it's a standard Ford removal.
There are special U-shaped rods that you insert into the holes, push
outwards a bit, and then pull the unit out. It's also possible to use
small nails or screwdrivers, but be careful not to push them in too far
or you can bend the tabs and make it almost impossible to remove.

I'm not certain about the Windstar, but on some Ford models, the
'radio' in the dash is just a control panel. The real radio is in a
separate module in back.

What I have done before is to cut up a metal coat hanger into a "U" shape
and use that. Be sure to file the sharp ends of the cut hanger.
It works by putting the ends in the holes and pushing outward/inward
(can't remember exactly) and pulling back on the wires. Stereo should
slide out.
Hope this helps