DVD Option didn't recognize. Disconnected Battery, not unit won't power on
 

I have a 2007 Tahoe LTZ. I recently took the unit out to replace the backup camera. Everything was working perfectly upon re-install. Then, the DVD option disappeared, and I couldn't find out how to eject the disc that was in there.

I decided to disconnect the battery positive and negatives. Let it sit for about 20 minutes. After reconnecting, the head unit doesn't do anything. Totally black screen, no lights. Any ideas?

Update. Went back out to the Tahoe. DVD Ejected. I pulled the fuse and reinstalled. It turned back on. So, the problem I still have is that the Disc option still isn't there. I tried inserting a DVD, but the unit didn't do anything.