When I open my computer it is left with a blank screen?

[WPCentral Question]

One day I was watching YouTube and I closed my laptop to go wash dishes. When I came back I opened my laptop it came up with the banner thing (shows time e-mails and battery). When I opened it, it is back with a red line going down the bottom and the right side of screen (this is a thin line). The audio was working from that video but and the mouse showed. Please help