My laptop won't turn on

Hello, i have a HP laptop that i bought about a year ago and it's working fine since then, but today i turned my laptop on and it was working fine, no problems at all. But, after 3 hours i tried turning it on and it won't turn on. I tried taking the battery off and turning it on, i tried pressing the function key and F6, F12 but my laptop still won't turn on.