Toyota Yaris won't start. Immobiliser problem?

[Pamela Dalton]

Hi, my Yaris won't start.  Had gone to get takeaways and had to wait some time so sat in the car with the key in the ignition but switched off.  Got out the car, locked it, collected takeaway and came back to car. Now it won't start.  Absolutely nothing.  No clicking, no cranking of engine.  Dash lights still come on but that is all.

[flash22]

Do the headlights come on ??