I have Lubuntu 14.04 running on a Sony VAIO VGN-FZ140E. My problems is: out of nowhere my monitor turns off, and no matter what I hit on the keyboard it doesn't come back. The only solution is to put it on suspend mode by closing the lid, then opening it again. The problem is that the brightness control doesn't work anymore after doing that, so I suspect it might be a driver or hardware problem, but I have no idea how to go any further on this analysis.
This is my very first question here, please guide me if I need to edit my question and/or provide any more information.
P.S.: Not sure if it has anything to do with the above issue, but it also happens that after the system is locked, there's no bright on the login screen, it's totally faded black.
Thanks in advance!