I'm having a problem with my CD playback. Now, these are the CD's that have been burnt onto the Hard Drive. Normally, using the TUNE knob, I can shuffle through the CD's on my hard drive. Well, that does not work any longer, so I'm not able to play any of my music on the hard drive. Is there a way to reset the settings on the unit to see if I can go back to factory settings. I'm just trying to see if there is anything I can do on my end before having to bring it to the dealership and spend a few hundred dollars. BTW, my vehicle has the full NAV unit with the upgraded speakers. Not sure if this makes a difference. Please help.