Do you have a system with a color display? If you do, what colour is the background of the "SECURE" message?
Try removing the fuse for the radio for 1 minute. Maybe it will restart.
If it still shows "SECURE", you need to drive your dealer with all your car keys and the PIN for the immobiliser. They will re-program the immobiliser so the radio will activate.
A.R.S., November 2012