okay so i removed an old car alarm to get it ready to fit a new one, but there was several wires that went into the siren(circuit) which i snipped to make it easier to take apart.

Now when i turn the key the power is there but not when you try to start it.

There a thick red wire from the ignition connected to a green wire and there is another thick red wire connected to a second green wire. both the green wires are in the engine bay an have no voltage across them. there is 2 red wires connected to the same source in there that accidently touch a green an nearly started before.

So i want to no how to rewire it from under the steering colum. is it just a matter of connecting the 2 thick red wires togheter and 1 power supply?

sounds like the greem wires would have been the immobiliser circuit. connect the 2 reds together and all should be well again

Thanks your were right just need to get a new soldering iron now.