2004 Audi A8L

I have a 2004 A8L and the MMI stopped working.I was travelling and stopped and gas station to refuel and when started the car the MMI screen was blank and lost audio as well.I tried to reset but no luck with that.All the lights on the control are out......when ever I hit setup or any soft keys the screen comes on with a MMI and than goes out in few seconds.I have checked my battery and it reads fine.I took it to a audi dealer and they could not figure it out..........they told me it has 7 total modules that they need to test at $110.00per hour.I have also checked the 60A fuse in the trunk and its good as well.I looked at the CD player and the lights come when I try to get the disks out.I have also checked the navigation unit in the trunk and the light come on and the CD's come out. Any suggestions......as to what I need to check..........any fuses or modules.



Thanks

Dave