engine will not turn when trying to start up. What can be the cause?

dose the engine turn at all if it dose then likely yhe timing is off or you could have a bad coil or somthing in the distrbuter has gone bad or bad plugs or wires. i had the same problum in my vega and all it was, was the timing spent over $700 on it befor i found the problum what is the egine (v6,v8... so on)