Hi,Thank you for asking your question today. It would help us to know:
Is the screen lit, a slight glo at all?
Can you see the menu if you use the RCA remote?
We're looking forward to hearing back from you soon!
From what you are explaining there has been a failure in the back light system. The back lights are the lamps that are internal to the LCD panel (screen) with out the back lights nothing can be seen on the screen. This is usually caused by a faulty back light inverter board as seen here. http://www.shopjimmy.com/lg-6632l-0580a-backlight-inverter.htm
Unfortunately it can also be caused by a faulty LCD panel too. So sorry there is no reset or easy fix for this to get you up and running, this is a internal circuit board failure and will require a repair. If I can be of further assistance please reply.