In order to operate the internal combustion engine in a car needs the following things:
1.Fuel
2.Spark
3.Air
4.Compression
The first thing to do is check for fuel. You need to hook up a fuel pressure gauge to the schrader valve on the inlet side of your fuel injection. While someone is cranking the motor read the pressure. You should have between 25-45psi. If you don't have that you have to proceed to troubleshooting the fuel system which entails checking the fuse (is it blown?); checking the fuel pump relay (jump it-does it click?);checking the wiring between your power distribution box to the fuel pump; checking the inertia switch circuit; and finally, jumping the pump with 12v to see if it turns.
Next is spark. Pull a spark plug lead off and hold it about 1/8" away from a ground (nut, bolt,spark plug). Can you see a spark? If no, try another plug. Same thing? Then you have to check the primary circuit for voltage and continuity. If good then you have to check the coil for resistance between the primary and secondary side (it shouldn't be infinity and it shouldn't be zero). If all that is good check for resistance on the spark plug leads. If all is good, you have to check the ignition switch and all of it's wiring. Is it grounding nice and tightly? Is the wiring in the power distribution box corroded?
Air is easy. Is the throttle blade moving ok? No birds have put a nest in the air filter?
Compression. I wouldn't worry about that. Your compression shouldn't be killed in all cylinders in just a few weeks.
Then there is the computer that controls everything (except the compression). Grab a scanner and check for fault codes.
I had a lot of time to kill at work so I wrote all this. I'd thought I'd give you an idea of what a mechanic would look for; and suggest that you visit a mechanic because I doubt you would have the tools necessary to check for all of this stuff.