'95 Stratus Factory Radio

I just bought a '95 Stratus. When I took it home, I noticed the radio wasn't working. I didn't think it was a big deal, I'd just replace it with an aftermarket stereo. Then the next time I drove the car, the radio worked. It worked for 3 more times of starting the car, and then stopped working again. Sometimes the clock will show up, sometimes I get nothing at all. Once or twice I got just two lines. I don't know if it's the fuse, or a short, maybe? I don't know much about wiring and all that. My brother knows some, but he lives an hour away. All I know is that it's confusing me, and am I going to have the same problem if I put an aftermarket head unit in? If it's a simple problem to fix, Id rather not waste the money on another head unit.

Thanks in advance.