Chevrolet Repair: 1992 halfton chevy, crank shaft, air cond

Question
I am currently driving a 1992 4x4 half ton chevy with a 350 engine a/c extended cab the truck sat out at our ranch from probably 3 to 4 months the only time being started to move out of the way. started driving it one month ago had an oil change, filters, nice little tune up now i just had the serpentine belt snap, bought a new on at the local parts store, come to find out the very bottom pulley is locked up is this normal or do i have a big problem here. thanks for all your help.

Answer
HI CHANCE,THE VERY BOTTOM PULLEY IS THE HARMONIC BALANCER.THIS IS THE CRANKSHAFT.IF THIS IS LOCKED UP THE MOTOR IS NO GOOD...GET BACK TO ME ON WHICH PULLEY IT IS WHAT DOES IT DRIVE,SUUCH AS AIR COND OR SMOG PUMP...NO PULLEY SHOULD BE LOCKED UP. THE CRANK SHAFT WILL NOT TURN UNTILL THE ENG IS RUNNING OR ENG IS CRNAKING OVER FROM THE STARTER..GET BACK TO ME..TOM..