96 sunfire radio problem

I just recently bought a 96 Sunfire SE. I changed out the radio. First, someone took out the factory harness, so I had to direct wire the new radio. What a pain. Everything was working just fine and then all of the sudden I have no sound and the radio won't pick up any stations. It still powers on and the cd still appears to play, but no sound. Can someone please tell me what is wrong and how I fix it. Thanks :)