power windows problem HELP ME!

ok, i have a 88 vert mustang *cough-4 banger*. the front left and back right power windows dont work at all. The other two work once in a great while. I'd like to do the fix myself but i have no idea were to start, besides the fuses and those are fine. Any idea or suggestions?

I would check the power window switches to see if they are gettin any power. From my experience in older stangs they are bad to short out, especially if they havent been taking good care of.

I'd agree my first step woud to see if the window switches are still working.

sorry, forgot to mention I already replaced the front driver side switches.