Monitor with possibly dead/dying backlight?

I received an older monitor as a gift from a friend of mines, an HP 2009m monitor, and I plug it in and it's working fine for about 3 hours. Then randomly the screen turns black and I can see everything that was on the previously lit screen, but it's all black and faint. I turn off the monitor and turn it back on and for about 3 seconds the backlight stays on and then it reverts back to the black faint screen. What would you guys say that is the problem, and how shall I go upon resolving it?