Help!?! Please

[69ChevySteP]

Alright so a few days ago my starter went out. I replaced the starter and after that the truck would have no juice in the cab or headlights or anything until I screwed with the wires (removed the pos and then connected it again.) yesterday it happened again and i removed and connected the wire but nothing still. I assumed a bad wire was the cause and replaced the pos and neg wires. They are in place tight and the ground is good. Still nothing anywhere. I checked the battery and its good, alternator good. What else could it be? help please I need to get to work. thanks