Sony start

My mini van will not start. It started about a week
and a half ago. I was getting ready to go to work
and it does on me in the middle of the road. I was
told that I had a bad battery and when ok got it
charged up I had it tested and they said it was a
bad battery and the alternator was good. So I took
my battery out and charged it up inside and took it
out the following morning and still no luck but my
neighbor helped me out the battery in and he didn't
tighten the battery cable to the battery right
enough. But I left it alone till we had some warm
weather and my dad checked it out and said a
number of things. I'm now very confused and
afraid that I may have busted a block I do not know
how I can tell if I did crack a block. A couple weeks
before it started dying and before the cold weather
hit it does on me when I was leaving school then it
started up again once I turned it off then about a
few days after that it over heated on me. Does any
one have an idea what's going on?