Ford Escape wont start

I have a 2004 ford escape...It is making a serious of fast clicking sounds from the engine, and won't start. What could it be?

That sounds like a bad connection at the battery. I'd remove the connectors from the battery terminals - clean the terminals and the mating surfaces of the connectors and then reconnect them.

Clean the mating surfaces with a toothbrush and baking soda and water. RInse well and reconnect. Put some petroleum jelly on the posts to keep them from building up deposits again.