newb, need help with radio

I have a 92 taurus wagon, and recently the radio stops working when I turn off the engine. When I start it again, the lights are on, etc. but the radio won't work. Also, if a tape is stuck in there, it will play it (with no sound or anything, just mechanically) non stop. The only way I have seen so far to fix it is to disconnect the battery, and essentially 'restart' my car. This spits out the tape, and/or makes the radio work again, but only until I turn the engine off. I think its prolly something with the wiring, but im not sure where or how to fix it....please help