Sand the entire sureface of the desk with 65 grit sand paper. Remove all paint and any debris that are on the frame of the desk.
Sand the surface of the desk using 80 grit sand paper. Smooth out all scratches and dents that may be on the surface of the desk.
Sand the desk with 120 grit sand paper. Smooth the entire surface of the desk so that it is even, then clean all the sanding dust off using a damp rag.
Allow the desk to air dry for about an hour. Apply two or more layers of spray primer to the entire surface of the desk. Allow the primer to completely dry for several hours. Make sure that the primer is on every area that you are going to paint.
Apply paint to the entire surface of the desk. Spray the paint onto the frame of the desk from about 6 to 8 inches in a side-to-side motion. Apply at least three coats and then allow the paint to dry overnight.