Step 1
Paint over the desk to cover up the old look and create something new. Sand the desk first to prepare it for painting. Use a medium sandpaper and work to a fine sandpaper. Wash the desk and use a primer appropriate for the desk's material. Allow the primer to dry and paint the desk with your chosen colors.
Step 2
Apply wallpaper over the desk to hide its appearance. Use craft adhesive, or another adhesive that will stick properly to the material of your desk, to attach the wallpaper. You can wallpaper the entire piece of furniture or just the top. Have a piece of glass cut that fits the top of the desk and set it on top to protect your wallpaper. You can also wallpaper just the top to save time and money. The top will add color to the room without making you work on the corners and other details of the desk.
Step 3
Cut a piece of wood or laminate that matches your decor and lay it on top of your desk, if the top of the desk is the ugly portion. You can secure this using an adhesive appropriate for the materials you are using, such as wood adhesive for a wooden desk and cover, or you can just set it on top if it is heavy enough not to shift around. This cover will change the look of the desk without having you fiddle with the remaining parts.