Chosen Solution
I connected my macbook on my television. When I disconnected the cable, my screen changed color. Since, colors are abnormal (a little bit fluorescent): I see almost nothing more. When I connect the mac on an external screen, everything works well.
I am providing you with a link to Apples troubleshooting guide for your problem. Please note the section on resetting your computer–being hooked up to the tv may have upset a setting. Since you have a good picture with an external monitor I believe your logic board is probably good. http://support.apple.com/kb/HT1573
