Hey Jimmy,
It sounds like you may have either a pinched cable, a broken cable, or a faulty display. I hope, for your sake, that it is only the cable that is pinched or disconnected.
Take a look at [guide|4773|this guide] to show you how to get the display cable out of the computer. iFixit also sells both the [product|IF186-073|data cable] and the [product|IF186-050|LCD], if it comes to that. If it comes to replacing the display, follow [guide|1498|this guide].
Since you say that the display turns off after a certain point, I suspect a faulty cable. For a start, check all the connections in the data cable, and inspect the cable for any tears or shorts. If the cable checks out, you may need to spring for a new LCD. Often the inverter boards on the back of these panels can go wonky after a few years, but this usually is usually demonstrated by the screen fading to white rather than black.