I had a locked car light come on in my 2006 chevy malibu, it no longer will drive. doesnt turn off, goes in reverse but when in drive, just revs like the car is in neutral, why?

Security lock out --key worn down not being read -- chip in key went bad --ignition switch problems ---electrical problem malfunction with vehicle security

The lock an car symbol is for the anti-theft system ! By not turning off, do you mean you can't turn the key to the off position or you can turn the key to off but the car won't shut off ?
It sounds like you have a Power Mode Mismatch
The ignition switch is an input to the BCM - body control module an if something happens to the system , the BCM will keep the vehicle in the last known mode Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the power mode master (PMM) fail to send a power mode message. The fail-safe plan covers those modules, using exclusively serial data control of power mode, as well as those modules with discrete ignition signal inputs.
You could have an ignition switch problem or something wrong with the BCM .
Discrete Ignition Signals Those modules that have discrete ignition signal inputs, also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, battery positive voltage, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 volts, the modules will fail-safe to OFF-AWAKE. In this state, the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
This is one you need to take to the dealer because they have a factory scan tool !