2005 Wrangler problem ~ Please help!

Please help! I have an 2005 Wrangler X. 4.0 with automatic. The other day check engine light came on. Drove it about 50 miles and came to a red light and it just stopped running. Tried starting a couple times and it finally started back up. Drove it to parts store to use scanner on it. It said that it was P0562, low or loss of voltage. I cleared codes and drove it home. Next morning it stalled again (no check engine code) and started again. Drove another few miles and came to light and it stalled again. This time it wouldn't start back up. Now all that I get is a "clunk" noise and I guess that's the starter. Took it out and had it bench tested. They said it was good. So, I had them check battery and they said it was bad. Replaced battery with new (under warranty) and put the old starter back in. So, we have new, rebuilt alt and new battery and I cleaned up battery and alt connections. Even the ground to engine wire. Went to start it and it just did the same "clunk", "clunk". I am at my wits end! I need to figure out what's wrong. My brother said "maybe engine is seized up" but how can that happen when the thing stalled and started 3 or 4 times before this? I need help. I need transportation to work and back and I hate to ask my dear, old mom for her car.