If it runs once jumped you're probably getting ignition juice from the alternator. Disconnect the battery while running to verify (if it dies you have a bad alternator) as even Optimas can be killed or fail. My yellow-top finally died after 6 years in 3 different vehicles. Hard to believe a 1980 has a generator, but you can pull up to an AutoZone etc. and they'll tell you for sure. Generators typically have a longer, narrower profile than an alternator since they produce DC whereas alternators make AC. My '75 'vette had an alternator and I haven't seen a generator on anything much later than the 60's models. Of course there's no telling what some braniac may have done to the car in previous ownership!