If the screen on your Lenovo Twist Ultrabook is displaying upside down or on its side, the easiest way to rotate the screen to the desired position is hold down the Ctrl key and the Alt key simultaneously while clicking the up, down, right or left arrow keys to change the orientation of your display. (Usually this is CTRL + ALT + Arrow Up).
If the key combinations don't work put the computer in tablet mode by laying the display 'screen side up' on the keyboard and then putting it back into laptop mode and try them again.
One way you can lock the screen rotation is to swipe from the right side to get the Windows charm bar, click the Settings icon, and then the Screen icon. The icon at the top of the brightness slide control can lock or unlock the screen rotation.
See also: Lenovo Power Management Driver for Lenovo Twist screen orientation changes