It depends on the OS. For Win9x you will need to use tweakui98 - it's still available on the Microsoft site somewhere. In XP - Right click on desktop. Click down to Properties, then open the Desktop tab. Click on the Customize Desktop button, then open the Web tab. Delete everything in the Web Pages box except, My Current Home Page. Press OK, then Apply, and maybe OK again. Possibly restart for settings to take effect. Should solve the problem. You will also need to ensure your wallpaper is in bmp format and not jpg or png - if memory serves correctly.