Infotainment system just stopped working

So it was working fine then just stopped all of a sudden when we started it up today. No radio, no navigation, no rear-view camera, nothing. When the car is turned on, you can hear it trying to read the CD. The lights on the nobs and buttons are on, but nothing on the screen, and no radio and none of the buttons do anything. Specifically checked the "audio" fuse and it is fine. Checked other fuses and didn't find any others that were blown. Disconnected the battery, cleaned the terminals, and checked the battery and it is fine, but still nothing. All the AC buttons and such that are underneath the screen work just fine. You can hear a slight buzz coming from the speakers if you listen closely, as if they are on, just not playing any sound. It doesn't matter if the car is running or just the accessories turned on. Worked on it for a couple hours but couldn't find anything obviously wrong. Thanks for any help anyone can give me.