Hi Sam,

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 the system may have shipped with a video card driver it can
also be used.

--
Regards,
Bert Kinney [MS-MVP DTS]
http://dts-l.org/
How to Configure Outlook Express for Internet News:
http://support.microsoft.com/default.aspx?kbid=171164

"Sam" wrote
my computer started displaying all my graphics in 16
colors and 640x480 yesterday. when i try to change it back
to 1024x768 and 32-bit color, it restarts but stays with
the old low res and low color settings. i can't think what
may have caused this.

any advice would be hugely appreciated as i now
essentially have a £1,000 doorstop!

thanks, sam