Lenovo G580 Notes
The screen started flickering and the quick fix is to push down just above the keyboard in the middle and then the flickering stops. Looks like a loose connection of the cable connecting the screen with the motherboard.
Lenovo IdeaPad G580 Laptop Screen Replacement Procedure: https://www.youtube.com/watch?v=smGMmZzm9bc
Lenovo G580 Laptop Disassembly video, take a part, how to open: https://www.youtube.com/watch?v=84lV68WRKlQ