does not load umd games

The PSP turns on and all functions seem to work properly except for the fact that it will not load a UMD Disc. The UMD icon is not even appearing on the screen. I just bought the system used on eBay and the previous owner had pictures on the screen for a wallpaper. I reset it back to factory settings to get rid of their pictures, do I need to perform an update to make it read the disc again? I did not try to play a disc before I reset the settings so I do not know if it was working before I reset it or not. please let me know if there's something I can do to make it play a game before I go ahead and send it back to the person I bought it from