my mac book pro 2011 never pass the grey screen.

I have a mac book pro 2011, 17". For some reasons it just stop working. I have recovered the OS by holding command-R, the problem still persist. I follow the note provided by apple here: http://support.apple.com/kb/TS2570 . Unfortunately, I have lost the recovered CD that came with my computer. What are the solution for this case. Please, help if any one has any idea about this issue.

The windows safe mode is working fine, but the Mac OS safe mode does not work. I have brought the computer to an apple technician to check for the hardware error using the tool provided by apple and found all hardwares to be ok. However, after try all the solution including internet recovery, the technician insisted that the mainboard is defected. What should I do to repair my computer?