How do you reset securiLock anti-theft system on 2003 Ford Taurus?

My car is locked up and won’t start. I think I may have screwed the security system up when trying to program a key remote for the car which never worked in the first place so I ended up returning the remote. The only thing is that I had done this like a month ago so why would I have problems now? Anyway my warranty is up and I need advice on how I can reset this to get my car started again. My stepson had disconnected the battery yesterday and that seemed to of unlocked it temporarily for today it won’t start again. Now is there any way to unlock this permanently so as not to to have further problems down the road? Please advise and thank you.

Press the unlock button on your vehicle’s key fob to deactivate the alarm. If you’ve misplaced your remote for the car, use the PATS programmed key to unlock the driver’s side door. Then, put the key in the ignition and turn the key to the “on” position. The vehicle’s battery should be on, but the engine shouldn’t be running.

Locate the override button on the alarm box, beneath the driver’s side of the dashboard. Press the button and hold it in until the alarm beeps one time. The LED light for the alarm should stop blinking, indicating the anti-theft system is disabled.

To reset the vehicle’s alarm, put the PATS programmed key in the ignition and turn the key to the “on” position. Press the override button. When the alarm resets, it chirps two times and the LED light begins blinking.