1978 Dodge Flair RV won't start. Ran for 2 sec. then died. Now engine won't even

[Larry]

turn over. Battery is good.? I recently purchases a 1978 Dodge Flair RV. Buyer said it runs find just needs a power steering belt. I ran around in it for a week just fine. One day I went to start it and it ran for two seconds and died. I immediately tried starting it up again and the engine won't even turn over. Nothing happens, lights won't work or anything. I had the battery checked and charged and it's good. Any suggestions would be greatly appreciated. Thanks