where is menu?

The player seems to open when the power button is turned on, but when I press the menu button, nothing happens. I have tried reseting it by holding the power on for 15 seconds. It doesn’t help. It just stares back at me…

The only other piece of info is that the player belongs to my sister, who is visiting from abroad. I don’t have this player or its software on my computer. However she needed to charge the battery so I plugged it into my computer (a Mac) vis the USB cable. It seemed to charge OK. Did the act of connecting it to my computer do something strange?

Thanks for any suggestions…

Carl