This is a really weird software-hardware problem. When I close my laptop lid, the screen naturally goes black, then, when I open it, there's a bar of blackness left at the top of my screen, about 100 pixels high. Okay, I think, might be the screen's fault, but I can move my mouse there, and when I click relevant elements behind the cover of darkness, they appear where they should be in the first place. Anyone has any idea what's going on?