92 Talon AWD Problem

I just bought this car off of someone and according to him it want crank and he got all kinds of engine code errors. The car has been sitting in a field since 1999. Everything powers up but it will not turn, spin, or crank. Do you think it could be a bad ECU. I was wondering if I was to crank it using the screw driver on the starter trick would that eliminate the engine itself as being a cause. The car has 105000 miles on it and the last time he tried to get it fix in 1999 the mechanic had no clue.