Hi
Question: Why do you want to format the player?
Try the HP Formatting Tool, you'll find it here:
http://files.extremeoverclocking.com/file.php?f=197
I know it looks like the Windows format tool, but beleve me it's not. This will erase everything, including the firmware. So you'll have to reinstall it after formatting. Hope it helps. Good luck
P.S. If your player's memory is below or equal 2Gb, use FAT sistem