Push up on the sliding cabinet door to release the bottom of the door from the track. Pull the door out and away from the bottom track and pull it down to remove it from the cabinet.
Check the tracks for warping. If the tracks bulge or are warped, use the screwdriver to loosen the screws and remove the tracks from the cabinets. Get a set of tracks to fit the cabinet and screw it in place. Replace both the bottom and top tracks.
Check the size of the cabinet door. It should be slightly smaller than the cabinet opening to move easily. Sand the top and bottom of the sliding wooden door to shave off about 1/8 of an inch from each side. Place the sliding door back into the cabinet and see if sliding it is easier. If not, remove the door and sand it by another 1/8 inch until it does slide well.