When I try to transfer music from the computer to my mobile phone using Sandisk Media Manager, I get a dialogue box saying that no device is connected. Does this mean that it doesn’t recognize the phone because the phone info hasn’t been uploaded to the PC, as with a camera that comes with a CD for the PC to recognize? My phone is an LG 800G, connected to the PC with USB cable, sandisk micro correctly placed in phone.
From the information you have provided it seems like the drivers for your phone are not installed on your computer. Take your micro sd card out and plug it into your computers USB or card reader with an adapter. Transfer the files to your card and then put your sd card back in your phone.