Doesn't run. Disconnect and examine cord and plug. If broken, repair (see
electric cord). If the switch doesn't seem to work properly (the push type often fails to catch when it is old) and if it is possible to open fan housing easily, replace the switch. Should these measures fail, take fan to a service shop.
Runs slowly. Disconnect, and turn fan blades by hand. If they feel stiff, apply a couple of drops of light oil either at oiling point (if there is one) or on shaft at the point where it enters motor housing. Turn blades to loosen them. Then, if shaft was oiled, remove oil with a rag.
Doesn't oscillate. Clean grease, oil, and dirt from oscillating mechanism under fan and apply a couple of drops of SAE No. 10 oil to moving parts.
Fan blades bent. Try straightening by hand. If this is impossible, take blades off shaft, lay bent blade on a flat surface and hammer out bend with a block of wood.