Hello I recently figured out why my android wasn't detecting that it was plugged into the usb on my computer, the cables I had were shite. So I went in and started trying to put music on my SD card. For some reason, there are only 7MB of memory left on the sd card, which i have not put anything onto yet. The only application I have installed on my phone is Maps. How can I erase everything on my SD card so I can use the music player!?!!?