I am Pete, and I'll be happy to answer your digital recorder question today.
The "PC" message will occur when the recorder is connected to a PC, or when a USB cable is connected to the USB port on the side of the device. If a cable is attached, then remove it.
If a cable is not attached, the connect and remove the cable several times to help get the recorder into an "unconnected" state again.
Let me know if that works out ok for you.