Leap Frog

[Renato]

Hello.

i have this problem on my Leap Frog 

when i turn off i lose sub master  memory  and date and time, but submaster memorized last year are yet present. Battery is new. If I try to re install OS the message is desk id is invalid. Running SETIDDSK, ID was set but trying to re install OS the message is the same. Help me please

[Renato]

The first Message when I try to re install OS is

desk id is invalid

the second is

serial number not recognised.