Here's the scoop on paint.

Lead paint should be approached with caution. Wear a respirator and work over plastic sheeting so that the dust / chips are contained. Lead paint residue can be disposed of as household garbage in all 50 states. You do not have to remove all of the paint even if it is lead. Just get the loose stuff off and paint over it. The new paint will seal the lead in and solve the issue.

If you want to know if you are dealing with oil or latex paint on the windows you have to test that paint. Take some fingernail polish remover and put it on a small piece of rag. Rub the rag on the paint in a small section. If it softens and removes the paint then it is latex.

Now....for your second question. The paint that you have on there needs to be properly prepped for a new coat of paint. You will have to thoroughly scrape, sand, and clean off all chipping, peeling, flaking paint as well as much dirt as you can get off. Once your prep work is complete then you are ready to prime.

The primer you select should be oil based primer. My experience has led me to prefer Benjamin Moore products. They cost a bit more than some, but are far better in not only application and workability, but also durability. Prime your windows with the oil based primer. (If your final color is a custom mixed color, consider a tinted primer. It will make your final coat easier and of better quality.)

The final coat can be oil or latex, that is your choice. Do you have a mildew problem in your area? If so, go with latex. Mildew lives off of the oils in oil based paint. Obviously oil is harder to work with and latex is easier.

Your final results will be comparable with either product as long as your prep work is good. The whole secret to a good paint job is prep, prep, prep.

Good gardening! and have fun painting....

Aubrey