text: If it's new or under some kind of warranty, I would try calling tech support if there still is one for Acer. I have seen this once or twice with IBM laptops in the somewhat distant past and the problem is likely in the switch that raises and lowers the brightness. We sent them off for repair. If this is a known issue with Acer, then they may likely repair it free even if it's out of warranty though you would have to pay shippng it there (and get insurance) to the repair center. Hopefully, it isn't he LCD that has gone bad - that can be expensive on a laptop. Also, you might look closely at the keyboard for an Fn (purple lettering maybe) key which will correspond to other purple writing above some of the function keys. There will be one that has some type of sun or light on it that will adjust brightness or dimness, you might tinker with these holding down the Fn key as you repeatedly press the corresponding key. This may be how you dimmed it though - just a thought. Good Luck!