The lights are a little irrelevant at the moment, unlikely that they are stopping it turning over.
But are possibly lit because you have been trying to start it without success.
Let's start at the beginning.
What vehicle, fuel and engine?
How did the non start happen, just couldn't start one morning or stalled or what?
Any noises like clicks from under the bonnet when trying to start?
What is the imobiliser light doing? (flashing light when you unlock)
Tried the spare key?