when I bought this car, the owner said that about a month previously, the car audio system just went dead..completely dead. There was a cassette stuck in the player, and I was able to get it out, but still nothing. No lights come on, nothing works...I checked the fuse and it seems to be intact. I've never heard of a car stereo just dying like that...radio, cassette, etc...any ideas that I might check before spending $300 or more to put in a new system?