I have the same problem.
I have a no-name iPod knock-off that has the potential to function very well, but I can't seem to manage the music and picture files.
There are two sets of 'instructions' - both useless.
The dial in the middle has the rewind and fast forward symbols, a 'M' at 12 o'clock and 'Vol' at 6 o'clock, with a 'play/pause' symbol in the middle. I bought it from Amazon -it might be a 'V70'.
If I push 'M', (Mode) and get to Music files, I can push 'play' and have 'Root' menu. Another click and I can play the files in there - however- I can only play the first album I downloaded onto the mp4 player. All the other albums and tracks are not accessible through the 'Root' menu.
I know that they are on the mp4 player because when I use it at work I play it through my work's computer and speakers.
I have tried alternative ways of managing the files, but to no avail. I am, however, no expert when it comes to file management.
Any ideas?