I tried flipping it - jeez it was so hard to move my mouse to 'revert' back to normal mode
If you are on Windows XP there must be a similar option under screen resolution/display properties or similar - sorry, can't remember XP settings at the mo.
Try pressing CTRL + ALT + a cursor key. On some PC's, this rotates the screen by 90 degrees. Whether you can do this or not is usually governed by the graphic card and drivers.