Car does not start?

Car started at first crank and ran. Then I shut off and tried again to start, and it did not. The ignition key goes flat in the cylinder, and I tried a new ignition cylinder, and it did not help either. The PRNDL light is on. The Oil Lamp Light is on, and the Radio is on in Dash. The anti-theft was on too. I tried to disconnect the battery negative cable to reset it and made no difference as the light still kept blinking. I checked all the fuses, and they are fine. Replaced the battery and the starter but no change at all. The same lights are still on. Need help as it is quite confusing on what the problem is. Thanks in advance.