Kia Spectra crankshaft will not turn

I just bought an 02 Kia Spectra. It has 9000 miles on it. I bought it from a friend who had it in his garage since 2003 when he bought it wrecked. It has front end damage. He said that when they parked it, the motor was not getting gas. They were trying to start it and he heard a backfire come from the air cleaner area. He said it would still turn over fine. Before I start on repairing the body, I wanted to make sure and get it running. The car would just click when you turn it over. Tried a few different batterys and even a jump start. Took off the starter and had it tested and it's fine. We have taken the plugs out and put mystery oil in the cylinders and soaked for 4 days. I put a socket on the crank pully and have tried to manually turn it over. It will not move at all. It appears that the motor is stuck. I just cannot believe that. It is an automatic 1.8 liter. I did not try moving the crank in nuetral. Not sure that would make a difference.