have you been shopping and put your car keys down on the counter where thay have a magnetic secerity strip like at boots, these can wipe out key codded ignition system and provent your car from starting.
or try disconnecting your battery, and put your foot on brake pedal to drain down the power to your ecu, leave for one hour, then re connect battery, this should clear any faults with the ecu, try to restart you engine.
try these, hope it helps