Vauxhall Corsa C (2002) 16v club warning lights?

The engine immobilizer light (an orange car with a spanner through it) has just started coming on, but it doesn't always stay on - sometimes it just goes out after driving for a few mins. Also the car is stalling occasionally and today the emissions light came on, along with the battery light - but when I left the car in a car park for 10 mins and restarted it, no more lights!? The EGR valve was replaced last year, anyone have any ideas? Thanks!