When you turn the key to "ON" ( the second click, or the position right before the one that engages the starter) do your accesories such as the HVAC fan, and such work? do you hear the fuel pump coming on (a hum coming from the gas tank) This is probably a fuse or electrical problem. Check the fuses for your ignition, fuel pump and any other engine related fuses or relays. Might also be a bad o corroded connection in the ignition lock or somewhere in that circuit - but is much more likely to just be a fuse.