Hm. It's not remembering its settings after a power off. It's possible that they blew a fuse somehow during the work. Check the fuses that go to the stereo, including both the car's fuse panel and any inline fuses behind the sled, perhaps a dash-dismantling is in your future. reference 1, reference 2, reference 3. Not sure if any of those are related, it may have nothing to do with any of that.

Another possibility is disk troubles. Try reference 4, reference 5, reference 6, and reference 7.