I turned off my gateway computer monitor and now it won't turn back on?

I had my computer for 4~ years and It's been working perfectly. There was no sign of slowing down, memory loss, or freezing at all, and one day, before I went to my friend's house, I turned off the monitor power and left the house. About 5-6 hours later, I came back and I pressed the monitor power button and nothing would come on. I pressed it again, and still nothing. I restarted my computer and I can hear my computer working perfectly fine, I even hear the little song right before the computer starts. The Monitor will not turn on. There is no orange glow on the power button, there is no blue glow on the power button, there is absloutely nothing. I checked all the connections and I pratically turned everything inside and out to figure out the problem; and still nothing. I thought it was my electricity outlet so I moved my entire computer to a place where I know electricity is running, and still nothing. When ever my computer monitor is plugged in, however, there is this gray (extremely faint) white box like thing that flickers on and off the computer screen. You can't see it in the light and hardly in the dark. I have Gateway GT5014 Media Center Computer, and I doubt my computer is the problem. Is there anyway to fix my monitor? I don't understand how turning off my monitor for few hours will cause that kind of damage to my computer. Thank you.