My MP4 player won't show files when connected

Hey there,
I have an unbranded 8gb (I think) mp4 player - worked perfectly for a while (got it as an x-mas present) but now when ever I connect the USB to computer to mp4 player it wil charge fine but won't come up with the folder with the options to go into the files to put a new song on. I have tried device manager but can't find it in their....it didn't come with a disk or anything. There is no reset button, although their is an option to 'delete all' Please help, I have a 3 hour journey tomorrow and want to put new songs on it.
There is no option for USB in the MP4 player menu (in setup)....although there is an option for online mode and the options are - Multiply Drive, Normal only and encrypted only. I have tried all 3 but it still is fruitless. Like I said though, it's charging fine which leads me to believe it's not the USB lead's fault.
I deleted every song off it by accident...was deleting pictures and it had an option for 'delete all' but it deleted everything....plugging it in it still doesn't come up with the folder...HELP ME!! I'm on a 3hour journey tomorrow with potentialy no music.