How Do I Disable Hot Corners In Mac OS X?
The corners are called Hot Corners in Mac OS X. To find them, click on the Apple menu on the top left of your screen and select System Preferences. Choose the Desktop & Screen Saver panel and then select the Screen Saver tab. There should be a Hot Corners button on the bottom left of the window. Click that button and then disable whichever features are enabled for the four corners.