Can't even see the sansa file on My Computer.

To change mode, the settings are on the unit. Push the Menu button on the upper right, at about 2 o’clock, and you’ll probably see Music (or Video, or Photos, or FM Radio, etc.). Turning the wheel clockwise Settings is right under music. Click the center button, turn the wheel to go down to System Settings, click the center button and turn the wheel again. Down near the bottom of the list is USB Mode. Click the center wheel, change it to MSC and then try to connect. Look for two new drives in Computer.