Clean up the track by vacuum using the crevice tool and scrubbing gently with a stiff brush to remove any caked-on material. Straighten the frame by gently bending it until it lays flat. Adjust the tension by adjusting the screws located near the wheels on the top or bottom of the door, which create or release the tension on the wheels effectively raising or lowering the door. Turn the screw clockwise half a turn to raise the door or counterclockwise to lower it and test to see if the problem is resolved. Replace the wheels or spring load, clean out the tracks, insert the replacement parts, and reinstall the screen door.