Did I do something to cause this if so what?

What is your question?

The problem started when the fan motor continued to run and drained the battery. I hooked up the battery charger connecting both the positive and negative to the battery terminal (bad idea I know). Battery charged car started no problem. Disconnected the fan connection on top of fan shroud, fan stopped. Disconnected fan relay, fan stopped. I figured it was most likely the temp sending switch ( based on what I learned from this site.) OK here where, the question starts here. The next morning I go out it starts no problem, one hour later, it won't start. it cranks fine, but wont fire, if you keep cranking it will eventually fire, run roughly for a few seconds and die. What did I do? Any ideas? I know I need to change the water pump and temp switch. but Why is it not starting?