No solution for me yet either, but you are not alone my friend.
I too run windows 7 64x
i5 2500k @ 4.5 GHz
6950 2gb @ 850mhz, 1320mhz memory
I have reinstalled every components drivers, reinstalled steam, uplay, and farcry itself.
I have tried removing the OC on both components, tried offline mode, tried all the internet tutorials I could find and now I'm stuck.
for me, it crashes without ever getting past the initial loading screen.
i am having this problem with far cry3 on u play any help please?