On the dash , sometimes light comes on with an X over the car image. What is this telling me ? Is it safe to drive ?

 

Bad battery in your key? That icon is the "immobilizer" icon. If the light is coming on while the car is running, you may have a bad key, bad battery in your key, or a short in the cars electrical system (most unlikely). It shouldn't run (fuel pump kill i believe) if that light is on, but I'd imagine it will continue to run normally as long as it was started with the key signal present.

 

Either the module in the key is bad or the immoblizer antenna ring is bad.If your car doesn't start and that is flashing then it is not getting signal from the key.