i just picked up a 95 cherokee, the guy said that the motor over heated and he went the next day to start and nothing it the motor turns over but does not start. i looked at it today and the motor turns over but the pulley is locked up, i was wondering what could cause this, the motor also has as i found out after i got it 265000 miles on it. i ont know what could cause the pulley to lock up ?

Are you sure that the motor is turning over. If the pulley is seized then that means the crankshaft is not turning and hence nothing is moving. That is the tell tale sign from consistent overheating and nobody doing anything to fix it resulting in the engine locking up. If the engine is locked up it will cost quite a bit to fix it and would probably be cheaper to buy a new engine for it.