Samsung laptop not starting

Hello,
I have a barely 3 years old Samsung notebook (940X3G). It was working perfectly fine until yesterday when it suddenly shut down. Maybe after i connected the cable to the AC adapter.
I have opened it and removed the battery and tried the hard reset (held the power button for 60 sec) but nothing happened. The green and blue lights are coming on when I plug it in the wall or I try to start it up. When I opened it up, I noticed that when i push the power button, the fans start for few seconds and then stop again.
I also connected the laptop to an external monitor that I used before but nothing happened.

I would appreciate if anybody here has any suggestion on what the problem could be.

Thanks a lot.