My 77 camaro only starts with cables, and then it would turn off as soon as I would turn on the lights. So I went to check out the alternator and it didn't work. After I installed the new alternator I started the car with the jumper cables and then turned on the lights to see what result I got and it worked now. Ok now here is the thing when I shut the car off, I cant restart it. Do you think its the battery now? It shouldn't be the starter right because it starts with the cables what do you suggest I try next.

did you let your battery recharge? if your battery was dead in the first place and you didnt let the new alt charge it up then it owuldnt have any charge to start your car again. start it up with the jumpers and let it idle for 20 minutes then shut it off and start again. then if it wont start i'd suspect your battery. if you can i'd try to get the battery charged first so you dont run the risk of burning out your new alt as it recharges the battery.

Yeah, I took the battery to get it checked out and it was 70 percent dead. It took 90 minutes to be fully charged. then I started the car, shut it off and every thing is good now. Something so simple, yet my experience lacks.

When putting a new alternator in a vehicle with a dead battery you run the risk of burning up the new alternator. Alternator are designed tho keep the charge in the battery not to recharge it from a dead state. I have to admit I've done it in a pinch but if you have the ability you should charge the battery up before running the car with the new alternator.