Turned on the phone yesterday morning, and the first thing I saw was that the wallpaper had reverted back to the original one the phone came with. Date and time were also screwed up, couldn't speed dial anymore, although the numbers are still in there. Music is no longer in the music player, photos gone. Hooked the USB to the PC to explore, but a message appeared saying that it needs to be formatted. If I reformat will I loose the rest of what's left in there, and therefore the functionality of the phone?