Win10 Monitor Rotation
This isn't actually a windows problem but more of a hardware problem associated with the graphics card. The image on the monitor can be rotated from its normal orientation by 90, 180, or 270 degrees.
The standard hot key combination is CTRL + ALT + Arrow Key which will rotate the screen image.
The work around is to use CTRL + ALT + UP ARROW which will orient the screen image back to its default position.
If you never require changing your monitor position from horizontal to vertical, then you can mouse down to the bottom right of your main screen in the system tray, and right click on the Graphics utility. In my case this was named "Intel HD Graphics" but yours may be named something different. It should however be apparent that its related to the graphics settings.
Right click on this icon and select "Graphics Properties"
In my case selecting "Maintain Display Scaling" disabled the CTRL + ALT + ARROW hot key.
For other utilities you may need to look for a box marked "enable rotation" and uncheck this box.
Save and exit the utility and you should be good to go.