Battery reset is the usual thing, disconnect for 20 mins then back on and try again.
Is the car low on fuel...under 1/4 a tank?
Have you just filled up with fuel?
Check the battery terminals are on tight, the earth strap isn't broken in the shrikwrap and make sure the piggy back wires are done up tight on the positive terminal.
Check you got fuel pressure first....open the bonnet, ignition on, with a key, depress the valve on the fuel rails to the injectors. It should shoot out 6ft in the air, watch your eyes and try not to get it over the hot engine!!!!