Hi Katie

This usually indicates that there is an incorrect video driver installed.
Here's some information on replacing the video driver.

Tip: Go to Start - Run and type Msconfig and press enter. On the
General Tab click advanced, and make sure "VGA 640x480x16 is
NOT checked before continuing.

To correct this you will first have to identify the video card installed.
That may include checking documentation, contacting the system
manufacturer, or opening the box and looking for identifying marks
on a video card or video chip on the mother board. Some systems
will display the Video Adapter information on the top of the screen
when the system first boots up. Some manufacturers displays a logo
screen that may cover this information. It may be able to be removed
temporarily by pressing the ESC key when the logo first appears. Once
the Video card has been identified, go to the manufactures web site,
download and install the latest video driver and install it as per there
instructions. Or if the system shipped with a video card driver it can
also be used. But the newest drivers are normally the best.