How To…Transfer music to your Sony w350 phone
1. Connect the w350 to the computer with the USB cord.
2. Open the Sony Ericsson PC suite (Media Manager) and click on File Transfer.
3. Move files from the computer to the device.
4. When you’re finished transferring your music, click eject and remove your device.

My phone w350 isn’t showing up in the media manager when I connect it.
My recommendations are as follows;
Be sure Media manger is installed on the computer.
Check the settings tot be sure Media Manager will launch when the w350 is connected.