Sony Ericsson w800i Dead Camera

[AmonRe]

My mate bought me a w800i in hong kong this week and when i got it yesterday all was working fine, then i went to test the main thing i wanted the phone for the Camera, and it did not work. Open the shutter and the camera displays a black screen then goes back to the main menu, leave the shutter open and then choose camera from the menu and it does the same thing, eveytime the camera fails. So then my mate upgrades the firmware, camera works for 4 hours, after that she has never worked again, any ideas? I was thinking maybe i reinstall the whole os on the phone as a reset does not work, anyone know of a hard reset or a way to reinstall the os??