It is possible that your battery is bad and has internally gone open circuit, in which case "jump starting" won't work. Are your battery cables clean and secure at the battery? How old your battery? A battery will typically last three to five years. You said the car won't start do the dash lights come on? Do you hear any sound when you try to start the car, do you hear a "clicking sound" that could be signs of a low battery or a failed starter /starter solinoed. Toyota have main fuse links at the battery positive cable or a main fuse located in the engine compartment fuse box, if these are bad the dash lights may not illuminate at all.