What can be the problem if the power windows don't work always on a 1993 cutlass supreme?

IT COULD BE A NUMBER OF THINGS.... IE.... ELECTRICAL SHORT IN THE MOTOR, WIRING, OR BUTTONS. TAKE IT TO A SHOP TO FIGURE IT OUT, OTHERWISE YOU WILL SPEND MORE MONEY TRYING TO REPLACE PART AFTER PART IF YOU DON'T KNOW HOW TO WORK ON ELECTRICAL STUFF ON VEHICLES.