Have you removed the battery cables and cleaned up the cable ends and the battery posts?

So with the key on the dash lights will come on. When you try to start the car there is a click and the lights go out? Sounds like a poor connection at the battery posts.

The connection can supply voltage with a low amperage demand (dash lights), but once you try to start the car the starter needs a lot more amperage and the poor connection at the posts can not meet the demand.

Try cleaning the cables and battery posts and snugging up the cables.

Randy