Craftsman Tractor Wheels Locked Up

My neighbor gave me an older Craftsman model 917.256451 tractor with mower, it was sitting for a long time but engine is free, we aired up the tires and i pulled it down the street with my Ford YT16H about 1/4 mile, It rolled free and great, I put it in my yard for a few days and today i went to move it and it wont roll. i jacked it up and the wheels move very free but in opposite directions??? Any suggestions?

picture of same model tractor