Check the blade fuse located on the driver's side inner fender just behind the battery by pulling it out of the white fuse holder. Look at it closely to see if the metal band is burned in two or cracked (cracks are hard to see). If you have a spare, replace it or install a temporary jumper wire to replace it. Check all the fuses in the fuse panel by the driver side door hinges. Remove the battery cable clamps (+ and -) from the battery and clean with a wire brush or knife. The + clamp has two smaller red wires connected to the clamp. Be sure they are making good contact. I've had to replace the + clamp twice in 300k ($3 at parts store). Turn on the head lights and hit the key. It the lights go dim, the battery is weak or the cables are not making good contact or the starter is bad. If the lights stay bright, control voltage is not reaching the starter solenoid that sits on top of the starter. At the fire wall, there is a gray wiring plug with six wires. One of these wires carries control voltage from the ignition switch to the solenoid. You can try moving the plug and wires a little while someone turns the key. The insulation on these six wires is extremely fragile so be gentle. A better way to test this is to run a wire from the + battery terminal to the starter solenoid terminal and see if the starter spins. I've got two 83 240's with 300k miles and the starters are still original on both (they are tough). Don't make to many sparks fly if you decide to try this stuff (take the - battery cable loose before the +).

is the battery dead? sure sounds like it. get a volt meter and check it. should be 12.5 volts or higher. crank the car and it should never drop below 10 volts. when it starts, make sure the charging systems works, 13v or higher at idle. good luck, chuck.

put the car in neutral and try to start it. if it starts then your neutral start switch is bad. good luck