why won't my macbook pro turn on

I was on my MacBook pro about 3 or 4 days ago, I shut my computer left my house and a few hours later returned. I opened my computer and it was unresponsive. I continued to press the power button to turn it on, pressed different keys but nothing happened. It charged fully and ha s been charging fine, there just isn't any response from it. Whenever it is closed the white light at the bottom right is bright, but when opened the light becomes dull. I'm not sure if that is important or not but I figured I should add all details. Also I only had a few tabs open of facebook and pandora. All of my updates are updated I'm pretty sure as well. If you could help me out that would be fantastic.