Hi Bikingat50,

Welcome to the forum, and great news that cycling has become a passion - you're amongst good company!
I second Tess's advice about taking the bike and the shoes to your local bike store, and finding which pedal system you like best.
From your description, it sounds like the spike/screw at the top of the shoe is there to help you walk in the shoe. I had a pair of shimano shoes which had lugs which screw into the top end of the shoe. They make it easier to walk, as you don't get the "duck walk" effect, as the shoe curls up towards the front.
I haven't described this very well, but basically they're there to help you walk in the shoe, when off the bike.