D100 image problem, please help!

I have inspected a camera body a lot of times )) - no any defects are found

I have made a shots with body cap and without it, and with closed viewfinder - effect is the same. Yes, I understand servicemen would help, but afraid in has no sense from financial point of view I already bought D300s so it is not to important but I love my D100 and do not want to say good by my old friend I just would like to get some help to identify problem. For example if it is sensor failure - it is final But I am wondered that in different shots different area of picture is normal, not the same - sometimes most left upper corner, sometimes much more area.

Anyway thanks for support, Kerry