Dell Precision M4600 won't start

I have a Dell Precision M4600 that just wouldn't turn on one morning. None of the LED lights turn on, and I can't get it to turn on plugged directly to the power source or through a dock. Dock LED light turns on, and green light on the power supply turns on. I tried unplugging and removing the battery for about 10 minutes. Nothing happened. Battery is new. Can someone please tell me what the problem is so I can buy the correct item to fix?