My mom brought me an LCD from her work doing the same thing. I took it apart, and it was totally filthy and dusty inside. I cleaned it all out, and used alcohol on some of the solder joints that looked corroded, and when i was done, it worked!
Start by taking it apart. There are maybe 6-10 screws on the back, and it just comes apart pretty easy. (Of course, make sure it isnt plugged in first…)