Try zapping the PRAM and resetting the SMC.
http://support.apple.com/kb/HT1379 Resetting your Mac's PRAM and NVRAM
http://support.apple.com/kb/HT1411 Apple Portables: Resetting the System Management Controller (SMC)
Apple Store said it doesn't have any nVidia problem, also it doesn't have that warranty period to change the logic board.
See Articles: http://support.apple.com/kb/TS2377 MacBook Pro: Distorted video or no video issues
These computers were manufactured between approximately May 2007 and September 2008
If your model applies, suggest that you call Apple Customer Relations - 1-800-767-2275. Ask politely & firmly that you want to be transferred to Customer Relations. Tell them exactly what you stated in your post. The repairs are considered on a case by case basis.
Thanks Baby Boomer
I did this before, but didn't work.
Thank's for your suggestion though.
Is there anything else ??
See my last paragraph------Call Customer Relations if necessary!!!
And resetting PRAM and NVRAM are the same thing right ??