2002 Oldsmobile Silhouette Potential short in the system

I have a 2002 Oldsmobile Silhouette mini van and I think I have some sort of electrical problem. This morning I drove the van to work and it ran fine with no indications of trouble. When I went out to start it after 30 minutes of sitting, it would not start. No lights were left on. When I turned the key to the start position nothing happened, but then when I turned the key back to the off position, all of the gauges jumped and I could hear the electric locks clicking. I was able to get the car jumped by a friend and drove it a short distance to an auto hobby shop where I attempted to replace the battery myself. I replaced the battery but not without struggle. The positive battery post was so corroded I had to break it off so I also had to replace the battery post connection and again this was done myself. With the new battery in, the car still would not start and when I wiggled the wires and rechecked the battery connection, I would get an occasional spark but not anything sustained. Is it possible to have a broken wire in the electrical system? Could that occur so suddenly without some induced trauma to the car? It was a sunny day and no rain. The battery was original so I was assuming that was the culprit, but now I'm wondering if there was some other short somewhere. Any suggestions on how to troubleshoot this? Many thanks for any thoughts. Mike Clark Michael. Clark@hanscom. Af. Mil