[MBAtarga]

I see DanDudley already posted the Garage Journal link - I was going to recommend you spend some time on that forum. Not knowing specifically what you have in mind for your garage floor "paint" - you need to exercise caution in prepping the current floor. You need to remove all old paint, stains and spots - preferably by grinding or heavily etching the floor. Anything less than an all out effort will likely end up in product failure down the road.