Back up all your files in the player to your computer.
Hook up your Key Ring Audio player.
At Start->Programs->Key Audio 256MB or Key Audio 512MB, launch the Firmware Manager. Check the current version of the firmware of your player against the one on the support site at http://www.philips.com/support. If a later version is available, download it onto your computer.
Uninstall the existing Firmware Manager application and then install the latest application, which you have just downloaded from the support site onto your computer.
At Start->Programs->Key Audio 256MB or Key Audio 512MB, select Firmware manager. Select your desired language option from the list and click Start to initiate the firmware installation process.
Once the installation process is complete, you may copy the files back into the player and click on the removal icon on the task tray to stop and eject the player.