Can't copy music to player

When I first connected my player to the computer, it showed up as a disk drive, even though it didn’t yet have a battery. I copied about 450Mb of music to it. Got home, inserted a battery, but nothing shows up as being on the media.

Connected it to my home system, but now it shows up as a m230. Formatted the device ( 3 times! ) Each time the format completes. Tried repeatedly to copy music, but I get the same error every time: " Cannot copy <song> because the device has stopped responding or has been disconnected."

How can I get this thing to function?

What OS are you using?

hmm, change to msc mode by going to settings, usb mode.

I get the same error whenever I try to copy more than 2 or 3 songs at the same time.  Then I try it again and it works fine.  I loaded it up with songs and it seemed to take forever because if I selected more than 3 at a time I kept getting the error and had to skip those songs.