It sounds as if the lens is not extending completely at power-on.
It should extend far enough to lock in place before anything will work.

That can happen if the camera has been dropped and it can happen if a grain of sand has gotten into the gearbox. Think back where you have been before the problem developed.

You can try an experiment;
When you power-on the camera and the lens starts to extend, grasp the lens housing and gently pull. See if that lets the lens extend further into locked position. If so, the camera should then work.

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