The Windows Magnifier is an Accessibility Tool that comes with Windows. It allows you to create a magnified area of your screen that can move around with either your cursor, keyboard or text editing movements.

If the Windows Magnifier starts when the operating system is loading make sure you haven't drag the Magnifier icon to the Startup folder. To see this click Start -> All Programs and check the Startup folder. In case you find the Magnifier there just right click it and select Delete.