I'm brand new here so don't flame me too much. I know the radio code issue has come up before but I've got a secondary issue.
I didn't realize I needed a code for the clarion radio in my '06 XL7 until after I replaced the battery. I aimlessly punched in random codes for a while. After about 10-15 attempts the screen now looks like this ----
I tried disconnecting the battery again but got the same thing.
I'm not that experienced either, but as far as I can tell, the only way to find out is to contact a dealer and/or Clarion tech support; they can give you the code based on the model s/n.