if battery is good and the earth on the back of the gearbox to the loom is ok lock the car with the fob, unlock it, ignition on but don't try and start the car, leave it on for thrity seconds to a minute, turn it off, lock the car with the fob, unlock again, switch ignition back on and after couple of seconds the imobiliser light should go out, then start the car:wink:
although don't be surprised if it turns out the car wouldn't start due to previous owner having problems with it and just blamed the battery.