by the way the problem of the unit why i am gonna do this is
when you call the screen get black display...
you cant see any thing just black display...
dont be afraid its not risky

must have 50% of battery
you must have ZUNE Software
and patience

check image below on how to...
Open Zune
Connect Unit on PC via USB
Install all driver @ Zune folder ( C:\Program Files\Zune)