Blank Screen

Hello, I'm having trouble with my computer/display monitor. Few hours ago everything was fine. I was cleaning the inside a bit, turned it on and...my screen wasnt displaying anything. Checked for lose cable, and everything was fine. Restarted it, and same thing nothing. I put on my headphones and turned the computer on and heard a beep and that was it. As well my keyboard lights up when I boot it up normally, but when the problem occured it doesn't up light up anymore. Any suggestions? Please.