It is probably not an anti-theft problem. You probably tripped the inertia switch on the fuel system. This is just a button to push on the Rh side of the passenger compartment near the firewall or kick panel depending on the year of your ranger. Let me know if this is the case, or the year of your ranger for a better location. If this is not the case let me know if you have an aftermarket anti-theft system.
Does it crank over?
Any lights on or flashing with the key on that indicate an abnormal condition?
How big of an impact was it?
Check your battery connections and check the battery voltage. It sounds like low voltage, these are all signs of this. Let me know. If there is no visible damage I would not think it would have knocked anything loose, but I have seen batteries fail for less reasons before.