Sorry I know too little french, hope you'll forgive me.
I have a similar problem, I guess, and I cannot solve it...
Everytime the battery gets out, I have troubles in recharging it with the USB cable.
At the beggining, the PC detects it, but the battery sign gets to FULL (because it gets the energy from the computer), but if I take out the USB (even after 24 hours), the battery is still EMPTY!
Until today, I switched it to ON, then OFF, then insert the USB, take it out, turn off, ... trying on and on, until (BY PURE LUCK!) it started to recharge the battery (the sign of the battery starts to show the recharging).
I really don't know HOW TO DO IT AGAIN!
And now it's 2 days that I try to do it, but I really can't find the "formula"... I spent more than 5 hours trying (put in, take out, turn on, turn off, over and over again), useless...
Can anyone help me? What is the right way to charge it? I need a step-by-step procedure (like: "1. turn the switch of the MPMAN to ON; 2. turn on your PC; 3. insert the USB and connect it to the PC;..."etc.)
Merci, thank you very much in advance for your help!