pull all the spark plugs out, and then try to turn the engine over by hand.
if a head gasket blew, and then the car sat for a while, coolant will seep into the combustion chamber and hydrolock the engine.
if the engine will turn by hand once the plugs are out, go ahead and turn the key and let the engine crank a few times to purge the cylinders. then quickly reinstall the spark plugs and start the engine. as soon as you get the engine running, take off the radiator cap, and give the engine a couple good revs. if coolant blows all over the place, then you have a blown head gasket.
also, if while the engine is idling, coolant bubbles out of the open radiator cap and smells like gasoline, that also indicates a blown head gasket.
of course, you can always just do a compression test.
When you changed the crank angle sensor were you VERY careful to fully engage the oil pump shaft on to the oil pump?
It sounds seized.
Do this, it works...despite what you might think. I had a chevy van lose all the oil all over the street and by the time i knew about it the engine siezed up. I did this, it works.
Drain all the oil out, replace the drain plug, fill the crankcase with diesel fuel, about 3 gal should be plenty. Take the plugs out. Let it sit for about a week. Try to slowly crank it with a wrench. If it turns over, drain the diesel and fill the crankcase with the requisite amount of "cheapest oil you can buy" and then try to crank it with the starter. If it cranks with the starter, crank it for about 15s then wait about 30s then crank it again for about 15s. Do this a few times. Replace the plugs (new ones) and try to start it. DO NOT DRIVE IT.
If it runs, let it idle to operating temp. If it is idling smoothly, drain and replace the oil with what you normally use.
It could be tranny related. Maybe the torque convertor locked up, but it sounds like your oilpump went. You have to either pull the tranny or the motor to investigate. If your top end is fine, then it's time for a rebuild, maybe a performance motor or just bottom end.
My car did that a few times about 100,000mi ago. I would be driving it then the engine would stumble and drag me to a stop. I had to let it sit for a minute then it would start up and run fine again. It seemed to only happen if I'd been driving with cruise control on for a long time.
I changed the battery and the problem stopped. It never did sieze on me though. And, I never really did find out exactly what the problem was.
If your engine hydrolocked while it was running you would have come to an instant stop, probably with engine parts all over you, the street, the cars around you, and any unfortunate bystanders.
Man...I almost want to drive to wherever you are just to fart around with your car. I'm really curious.
You might have stuck injectors. If you did, your mixture would suddenly go very rich and the engine would probably stumble and die and the slow trickle of gas in to any open cylinder may be enough to hydrolock the engine and keep you and that starter from turning it over. It'd be easy to figure out, just pop out the plugs. If gas trickles out or it even smells strongly of gas, that might be it.
2002 Mustang 3.8L Appears Seized - is this common? 
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