Pull the drawer all the way out. You may need to raise the front of the drawer and lift the drawer to remove it completely.
Examine the drawer glide on the drawer. The glide is usually on the right side or the underside. Also examine the glide inside the desk or cabinet from which you removed the drawer; it is in the place that corresponds with the glide on the drawer, whether it is an undermount or side-mount glide.
Install a replacement mounting screw into each glide in which the current screw is stripped or missing. Tighten each screw to secure the glides in their proper position.
Straighten bent areas of the glides, if necessary, using a pair of pliers.
Remove the mounting screws from glides that are damaged beyond the point of simply needing straightening. Take out both the glide on the drawer and the glide inside the desk or cabinet. Mount replacement glides that are the same design as the old glides. Position the new glides using the previous side or bottom configuration on the drawer and within the desk or cabinet. Secure the new glides with mounting screws, using a screwdriver to tighten them.
Reinstall the drawer inside the desk or cabinet. Slide it out and in to ensure it moves smoothly.