Finally found a laptop and flashed a backup image to the card.
There was an error while flashing, so I had to use another card that flashed OK.
I couldn't check the partitioning of the original card because windows were trying to format it repeatedly, so I have to return to my box for further info.
It might be my bad luck after all..
(
For now, I will disable the USB mode anyway and be very careful while charging, because it will be difficult to find a PC again..