My car's FM (haven't tried AM) stereo keeps turning off. How do I fix it?

If the radio it self goes out, the whole screen goes blank, and it does not loose its memory, then it will most likely be internal of the radio. If the sound just cuts out and the radio stays on then it might be the amplifier. We always suggest having it diagnosed by someone with the equipment and knowledge because in the long run it's less expensive then guessing, especially on electronic parts.