answer:I’d guess one of two things, both based on the fact that it clears up when it heats up. One, could be a loose or possibly cracked ribbon cable from the mainboard to the display. You want to open up the case and physically inspect the ribbon cable, and reseat the cable connections at both ends. Two, possibly a failing video controller, which starts working better once it warms up. That could be a poor solder join or loose socket (unlikely that its a socketed chip) that doesn’t make good contact until it expands. Option 1 strikes me as the most likely, since you don’t mention tearing or streaks or dead areas on the screen. If you don’t mind going into the case, I’d bet you could fix this.