Won't turn on

Hello you guys, so i got a MB from my brother and he told me its been off for two years due to him losing the charger. Well I bought a new one and it was charging and still does but as soon as i hit the power button it sounds like its trying to turn on but than turns off right away after hiting the power button. Just trying to see what could be the problem. I have tried every way to get it to start changed the RAM and battery I even sprayed Duster spray on it to clean it and it still doing the same. Just need help please.