How to get the monitor screen back to normal state?

At times, by mistake you type something and the monitor screen turns upside down suddenly! Well, well well, DON'T PANIC! This is pretty simple fix to be implemented. All you need to do is press "Ctrl+Alt+Up Arrow" if it would have been turned upside down. How to take it inversely? Its the opposite, i.e., "Ctrl+Alt+Down Arrow". If you want experiment on the side arrows as well similarly but this would make the screen to rotate 90 degrees left or right. Hope this helps. Cheers!