I just went through something similar with my Dell W1700 lcd tv/monitor. It was a bad backlight inverter.
Got a new one from www.lcdpart.com
and a neghbor helped me install it.
I got pictures again. Had been listening to television for six weeks.
I would suggest folks looking for a lcd tv/monitor that Samsung looks really good and has a three year warranty. Forget Dell.
If you've got your screen apart, check out the backlight inverter.
Hope this helps