First of, pardon any spelling mistakes that i might make. I have a really odd problem with my Laptop, Lenovo Z500, which i simply can't fix on my own. After a few minutes of normal pc usage on my external monitor yesterday i realized that my laptop-screen had suddently become very, very dark. My first thought was that i might have accidently changed the brightness whilst playing or something, but the brightness would not change at all. (Now, before you come up with silly things like these; Yes, i have tried to switch it off and back on. Yes, i have tried to fix it using the energy-settings. And yes, i have tried to roll back/ reinstall both my nVidia and Intel HD driver.) The problem did not vanish, and my laptop screen is so dark that i can barly see anything. The external-screen still works fine, and the problem did not occure when i started the laptop but a few minutes after . Thus i might take the guess that this is a software/ settings problem, but i simply can't find any serious solution to this problem anywhere. I really hope that some of upcomming patches for Windows or some new GPU-drivers might fix this soon, but i do not want to send my beloved laptop to a expensive repair. Please, help me! My System: Intel Core i5 - 3230m (2C / 4T @ 2.6 - 3.0 Ghz) 8 Gb of DDR3 Ram GPU 1: nVidia GT 740m GPU 2: Intel HD 4000 HDD: 1 Tb SSHD OS: Windows 10, 64-bit all up to date.