NO DATA appears on the sreen
Reformatting your player will delete all existing data files which you have personally installed on the unit.
Reformatting does not however, delete any drivers or firmware.
If you enter the menu and look for your System Files folder, you should be able to determine if your firmware is still present.
If you're concerned, just go to the manufacturer's website and download the latest firmware for your player, save the firmware file onto your pc, connect your player to your pc and transfer the firmware file directly to your player.
Follow the installation as per the instructions.
Hope this helps.....