Hi Airclues.....
Sounds like someone has reset your display properties. Unlikely to be Y2K or hacker related.
In Windows, go to Start/Settings/Control Panel/Display.
Click on the 'Settings' Tab - (far right).
Look at the Colour Palette and Desktop Area fields. Increase the Destop Area settings - eg to 800 by 600 pixels. That should fix it. Check that the Colour Palette is set to 256 Colours or greater.
Email me if you have any more problems.