Answer:
It means your resolution is set too low. Here's how to fix it...
XP:
click Start, click Settings, click Control Panel
open Display (you may not see the Display icon. To correct this, click Switch to Classic View.)
In the Display Properties window, click on the Settings tab.
Locate the Screen resolution slider on the left-hand side of the window and move it all the way to the right.
Vista:
click Start, click Control Panel
click Adjust screen resolution
move the Resolution: slider to the right