To make sure it does not happen again, follow these steps:
Right click on your desktop, choose graphic properties...
Look for Display Settings, and then look for a checked box that says Enable Rotation. Uncheck that box.
By disabling rotation, you take away the chance of this mistakenly happening in the future.
Note: The steps may be different for different computers and graphics cards, but the key is to disable rotation.
Community Member Since 2003