isight camera has never worked and have replaced all parts and main board

I have a macbook pro (15in early 2008), the isight camera never worked, but it was never an issue until now. Now I need to use it so I replaced all the camera parts and connectors. I have also replaced the mainboard because of the NVIDIA recall. The thing STILL doesn't work. Any suggestion other than paying Apple a ton to fix it? If it is a part I haven't thought of I can fix that myself...I just can't imagine what the problem could be after the replacements.