My JVC headunit won't work!

Hey guys, I am a total nOOb in this, but hey, we all started somewhere right?

Well. here's my problem. I got a JVC headunit and installed everything and it was working perfectly. Then I decided to uninstalled it again, just for fun, but when i plugged everything again, it turns on fine, and i can play cd's too, but for some reason the radio won't work. I really have no idea what's the problem. Can anybody offer some advice??

Thanks in advance!