If you have a lenovo laptop with a Dim Backlight, and a LED Screen, the cause is most likely a blown fuse on the motherboard. In most cases newer laptops, are using an LED’s instead of CCFL‘s, which negates the need of an Invertor, so now manufacturers are placing a fuse on the motherboard, to protect the screen from surges. However sometimes a momentary problem can blow this fuse, and kill power to the screen rendering the computer unusable. however with a little time, and a lot of heat (soldering) you can replace this puppy. Jump over to this post to get the link for the FUSE you need.