I think Cougar interpreted that as a full cranking of the engine with no firing up problem. The description sounded more to me like a no-cranking situation - as in you just get clicking noise when you turn the key.
Anyway, if that is the story then this is often a simple matter of dirty/corroded connections at the battery or thereabouts. Clean your battery terminals up really well. Follow the cables around and clean up any connections you find from the cables - grounds are especially important. If cleaning things up doesn’t work, start splitting the insulation on the cables looking for hidden crud underneath.