The maker's info (for Siren V) in Japanese is available at the following address:
Basically download the firmware update, unzip (if needed) then doubleclick on the setup icon. After the progam installs (if you go with the default settings) you need to press and hold down the menu button (right side button,looking at the screen)on the MP3 player, plug into your computer via usb cable and hold in that menu button till the computer recognizes the mp3, then release.
Next, go to your start menu look for the siren program and choose 'update firmware'click on it. A window should pop up (possibly in Japanese) It should have 2 sets of firmware numbers toward the top of the screen box,mine were the same (I think its what you have installed on the mp3 and what the proram has to install instead, the update) On the left of the screen halfway down there's a tick box that's asking if you want to fomat the player, tick the box to say yes. then click the start button at the bottom of the screen (the left button, the right is cancel). A 'do NOT remove the cable while the update is working' warning will come on the screen and a progress bar will show whats happening. When its finished, the button sign will change and the left button will have tojiru, 'finish' in kanji, click it and you are done, your Siren V mp3 player should be resurrected Halelujah!