Try turning the computer off and then start it up in "Safe Mode" (instructions below). If it loads fine in there, then it is something on the device. Accidental change of settings (it happens), virus, malware, bad program, etc. Which would have to be removed (or fixed if in settings) and then it would show fine.
Now if it does it in "Safe Mode" too, then it may be a bigger problem. Then I would try an external monitor to see if it shows up that way on it.
How to enter "Safe Mode" when booting the computer.
In Windows 8 and 10...
As your computer restarts, press F8 (possibly a few times) to enter "Safe Mode"
a. Press the "F4" key to Enable "Safe Mode".
(The computer will then start in "Safe Mode" with a minimal set of drivers and...