96 toyota camry won't turn over

Car: Toyota Camry LE 4cylinder

What happened: I was on my way up a steep grade (Morongo to Yucca Valley in case
anyone knows) and out of no where my car starts to decelerate and I was able to pull to
the side before my car locked up on me. My coolant overflow was squirting all of the
coolant out of the container and I just left it there to get towed. About 1 hour later it is in
my driveway. My dad and I took the thermostat out incase that did anything, we got in to
the car to see whats up; we filled it with water and drove down the the street. Not even
one block down and my car locks up again (no spewing of coolant though). Pushed it back
down to the front of my house, waited about 30min and tried it again... could barely turn
over. Found out that the more we tried to start the car, the negative cable on the battery
started getting REALLY hot.

What we did: Checked the timing belt (good). changed the negative cable and cleaned the
ground connections (Good) tested the starter (Passed) tested the alternator (passed)
charged and tested the batter (Passed and 100%) Jump start car (No effect)

The only thing I can think of is that the engine is seized but if that was the case than why
would it run again after the initial breakdown? I can hear the solenoid pop out and the
starter motor was tested good. I was hoping it would be a sensor issue or something but
the repair book claims that only the V6 models have crankshaft position sensors. There's
got to be a way to fix this! please help!