Sounds and discplay

This varies by operating system which is why it is a good idea to post the brand, model, and operating system with a query.

For a Samsung Galaxy 10.1:

Type apps is the upper right corner. Then tap Settings from the all tab. Then in the left menu, tap screen. Then, tap auto rotate
For the Inspiron Dell 2-in-1 with Windows 10:

Go to Control Panel> Display>Change Display Settings and then make sure that the "Allow the screen to auto-rotate" is selected. Or try the following: Place the tablet into Pad/Tablet mode.
Click the Start Start menu and select Settings. Click System.
Click Display. Scroll down and toggle Lock rotation of this display to ON.

Or this might help:

Click the Start Start menu and select Settings. Scroll down and toggle Lock rotation of this display to OFF.

Hello,
Auto Rotation

1. To open the Notification Panel, swipe down from the top of the screen.
2. To stop the rotation, touch Auto rotate in the Quick Setting Panel.
3. Depending on the screen orientation when touching the Auto rotate icon, the icon changes the screen to either Landscape or Portrait.

BEST OF LUCK !!!!!

1. Tap on the top right corner of the Home Screen to access the tablet > utilities.
2. Tap Settings > Screen.
3. Tap to deselect/select Auto-rotate screen.

You should be able to just turn the tablet on its side an the screen would auto rotate but if not go to settings an select screen settings/display an change the setting to auto rotate.

in settings there is a section that you can turn auto rotate off you need to do this if you want it to stop rotating , you might be able to access the setting from dragging the menu bar from top of screen down like on a samsung

The operating system might be busy loading itself, and when you move it, that takes precedence over lower functions.

Have you waited for it to boot without moving it to see if it auto corrects?? If it does not, then you might have a problem with the sensor.

The Auto-rotation setting must be disabled. Enable it on the settings menu. Or if your tablet is running iOS 7, then enable auto-rotation on the Control Center. Simply swipe up from the bottom of the screen to launch control center. (It is like the opposite of pulling out Status Bar or Notifications Bar above.)

Do you mean the onscreen text or pictures don't rotate when you turn the tablet sideways? If so, on the Home screen tap Settings, then scroll all the way down the settings past the bottom of the screen. Near the end of the list is Accessibility. Tap that, and then in the System section be sure there's a check in the box next to Auto-rotate screen. If there isn't, tap the checkbox to put one in. Then press the back arrow till you're back at the Home screen, and when you rotate your tablet the pictures and text should remain horizontal.

sounds like you have some dead pixels. There is no solution except to replace the screen

Some tablets will have a physical rotate lock switch. There is also a setting that locks the rotation. Settings > Display. Auto Screen Rotate.