I got called to fix a computer screen that suddenly displayed upside-down. I'd never heard of this before except on a TV show about ghost hauntings. I showed up at the store and confirmed that the screen was, indeed, upside-down. After a quick search online, I discovered that a quick CTRL + ALT + ARROW (up, down, left, or right) would change the orientation of the screen. I used the key sequence and corrected the problem. The computer with the problem is running Windows XP.