Is the blink from green to orange continuous at a steady interval?

If so, then that may be the death knell for your display.

If not, then it is probably the signal coming into it.

Shut the system down, unplug power, then unplug and replug both ends of the video cable.

If that doesn't fix it, try the same display with another computer and a different display with this one. Also a different cable if possible.