1) You have to enter in safe mode by hitting F8 right before you get to the Windows 2000 Logo Screen.

After you are in safe mode, you will enter Control Panel, System (icon), Hardware tab, Device manager.

Here are some screen shots on how to disable your onboard video for Windows 2000 Professional.

Control Panel

System Properties

Hardware Tab

Device Manager

Right click onboard video and select disable

Select yes after clicking on disable

Now select YES to restart

After Windows is done restarting, you will see your onboard with a RED X. That indicates that it's now disabled.