I just read something about this the other day. I think it said that if your paint comes off with rubbing alcohol, it is latex. If it doesn't, it is oil. a]Correct!- acetone (nail polish remover) will also work.
I think you will have to use a special primer if it is oil and you want to use latex over it. Have you tried asking at a paint store?-correct again....if you want to use latex paint you'll need either a special Latex primer - BM has one called "FreshStart" or you can also you an oil primer and the finial coat with latex, but then your primer coat is that yucky oil primer smell & clean up that your trying to get away from.