Car wont turn over?

What is your question?

I just bought a 1997 deville d'elegance. Car ran great for the first couple hours then got a overheating engine light and low coolant light. pulled over, white smoke was coming from serpentine system. I try to start it but wouldnt turn over. I let it cool down filled up will coolant, it would just vanish. I looked for leaks and found no ripped hoses. Changed the oil, there was water in it. Why was there water in the Oil? Car wont turn over?