Hit CTRL + ALT + Up Arrow and your Windows desktop should return to landscape mode. You can rotate the screen to portrait or upside-down landscape, by hitting CTRL + ALT + Left Arrow, Right Arrow or Down arrow.
In order to fix the sideways screen on your laptop, you will first need to shut down your computer. Once that is done, you’ll need to look along the sides of your laptop screen for a button that looks like it’s in the shape of a rectangle with a rectangle inside of it.
If your screen is flipped sideways, it means you have accidentally rotated your screen. This can be fixed by going into your Mac’s System Preferences menu, then into the Display settings and then clicking the Orientation icon. Click the drop down menu and select Landscape.