according to the article
"If you are still unable to start up your computer after trying each of these steps, schedule a service appointment with an Apple Retail Store or an Apple Authorized Service Provider. If you plan to visit an Apple Retail store, make a reservation at the Genius Bar using http://www.apple.com/retail/geniusbar/ (available in some countries only)."
You should try resetting the SMC. I would say about 25% of the computers I see at the AASP where I work that don't turn on can be fixed by simply resetting the SMC. The instructions for this can be found here.
If this does not solve the issue, I would recommend taking it by your nearest Apple Store or Apple Authorized Service Provider.