I have a Ford Taurus that makes a grinding, screeching sound when I attempt to start it. We have recently had trouble with it over heating. My wife said right before it died on her it felt like the car slipped into overdrive but the car was losing speed even though she tried flooring it. Added info- The engine will sometimes turn over a couple of times before making that aweful sound.

Who has answers?

They sound like unrelated issues.

As far as starting, sounds like either the starter gear or (more likely) the flywheel is stripped in places. The flywheel has a gear around the outside that the start engages to spin the motor.

Not something you should attempt to fix unless you know what you are doing.

Example image:
http://www.mcsorley.net/locost/powertrain/images/TrannyMate01.JPG


The part in the upper right is the starter.
If the teeth on the flywheel strip out, the starter can't spin it.