Monitor screen turned 90 degrees.

I would like to let you know that you need to press and hold 'Ctrl' + 'Alt' keys and then the Up arrow key on the keyboard to rotate your screen to the normal position.

Also, for your information, I would like to add the following tips:

1. If you press and hold 'Ctrl' + 'Alt' keys and press right arrow the monitor display will turn in anti-clockwise direction.
2. If you press and hold 'Ctrl' + 'Alt' keys and press left arrow the monitor display will turn clockwise direction.
3. If you press and hold 'Ctrl' + 'Alt' keys and press down arrow the monitor display will turn upside.

Likewise, if your monitor display has rotated in clockwise or anticlockwise directions on a Windows XP Home Edition computer, you can turn the display to proper position by following the first step.