K750i~w800i Camera Help please !!!

Can Somebody Help ?
I have recently purchased a sony ericsson K750i off of ebay that was upgraded to an W800i with the understanding from the buyer that the camera works now & then...i have re-flashed the phone with the original K750i firmware from this site and the camera does'nt work i then re-flashed the phone with W800 software and still no luck however the camera itself has no problem as i removed the camera from my phone and fitted it in another K750 and it all works but when i put any camera including a brand new one i bought off of ebay into my phone im still having no luck?
When i selecet the camera from the menu screen it selects the camera and then goes instantaniously back to the menu...if i select the camera by pressing the camera nutton on the side of the phone the cam screen loads then goes straight off so any help would be appreciated thanks :D

Phone Model:
K750i~W800i firmware
RIBC002
CID36
COLOUR:RED
EMEA_6
CDA102430/6 R2A