[wvguy]

well, I am so not a fan of paintng concrete but if you must heres what to do.
first check for moisture by placing plastic on the floor , say a baggie. tape it down. wait and see if you have moisture the next day if so . don't paint.
if it is peeling you have to remove all that you can. many different methods but the best is what is working the best for you. pressure washing, stripper, or the ole wire brush.
then oil based paint is my professional choice.