Why won't my the backlight on my laptop come on all the time?

My Acer Extensa 4420 backlight has stopped coming on. The odd thing is that when I go to a game or let it sit on the screensaver for a elongated period of time it will flash back on for 30 seconds or more and then it turns off. Just recently my screen had started working again for about two days but now it is back to it's old flickering self. I do not thing it is a backlight problem, but what else could it be?