If the display will no longer rotate, such as after installing a Windows update, some possible causes and solutions are as follows.
Verify that screen rotation is not disabled (locked) in the Action Center. To open the Action Center, you can swipe from the right edge of the screen, or tap on the bottom right Notifications icon. You may need to expand the bottom options.
Some installed application software may lock the display and prevent it from rotating, perhaps just while running. Close the running application, or use End Task in Task Manager. The software and settings may need to be fully removed.
Intel HD Graphics Driver update for Atom Z3700 Processor
The latest graphics drivers should install automatically through the default Windows Update service on the FC-5000.
If needing to install manually, the latest Intel HD Graphics driver updates for the Atom Z3700 processor are available to download here.
Review the display settings
If you have ever attached an external monitor (such as through the HDMI port on the M2 Dock), you may need to remove previous dual screen settings or set the built-in display to be the main screen again.
You may need to perform a reset by navigating to Start > Settings > Update & Security > Recovery > Reset this PC > Get started.