Problem with my n73 camera can anyone give me advice?

I'm living in the u.k, and just bought a nokia n73 from ebay, so ist not like i can take it back to the store. When using the camera there is a small black mark on the screen, like there's something on the lens, but on closer inspection, the lens is clear. Any suggestions, on how/where to fix it????Problem with my n73 camera can anyone give me advice?
You upgrade software version


If not possible format your fone,


otherwise 100 % problem in display or your camera lense,


also check cover of ur camera lense,


thanks.