Starting disabled

What does the security light do when you turn the key on? How about when you try to start it? What occurred just before this started? Is the battery fully charged?
Do you have more than one key?
The common failure point in these is the wiring from the ignition cylinder that reads the resistor chip in the key. Also have seen the contacts get dirty, for that some alcohol on a swab and rub the key and inside the lock by putting a large drop of alcohol on the chip and sliding it in/out to scrub the points in the switch.
If none of that works. The cylinder will need to be replaced.

These wires are attached to the key cylinder itself. The break because they flex with every turn of the key. They run inside the column in a shield and to the security part of the computer. I asked about the light because it can assist in determining what is wrong. For instance if you put the key in and try to start the engine and the light goes out the key is being read and the failure is somewhere else. If you put the key in and the security light stays on then it is likely that it doesn't read the key.