"Music Center for PC" does not recognize the A100 series or ZX500 series.
Try the following operation.
Disconnect the Walkman from your computer, and then reconnect it to the computer with a USB cable .
When the message "Use USB for" is displayed on the Walkman screen, add a check mark to [File Transfer] and select [OK].
If the message "Use USB for" is not displayed on the Walkman screen, unlock the Walkman.