From easiest and most likely to hardest and also likely.
Check all fuses in the relay box under the hood, something may have fried.
Check the ground strap at the back of the intake on the passenger side, this being disconnected can cause problems.
Check the red relay box under the dash about a foot directly above the brake pedal, is it buzzing with the ignition in the "on" position?
Make sure you maf connections are snug (though the car would likely fire a few times even if it were not.)
Was the timing belt serviced recently? Pull off the inspection cover for the timing belt on one side and make sure that you still have one.
Check the connection to the cam angle sensor.
Pull the codes from the ECU (see the how to at the top of the forum)
Is there an after-market alarm? Disable it.
See if replacing the entire car solves the problem, if so replace car, and nuke current car from orbit.
