only turns on when plugged in, dead when unplugged
 

my mp4 player was workin fine, then i pluged it in go my cpu w/ the usb cable to charge, & it did charge, but when i unplug it its dead, nothing happens. i can plug it back in, still shows a full charge, & it will play music & vids, etc only while pluged in, i can even have it on & playin music while pluged in & if i unplug it while playin music it shuts off. i even left it to charge over night w/ same results. its fairly new & barley used, & i havent messed w/ the firmware or anything.

1.main power on/off switch problem
2.replace battery

I'd say almost certainly faulty battery.

Re: only turns on when plugged in, dead when unplugged
 

the on/off switch works, b/c it works while pluged in. how do i cange the bat, there is in placxe for one.

that should DIY. open the player take off battery.go buy compatible Li-ion battery.replace.

Re: only turns on when plugged in, dead when unplugged
 

when i plug it in to my cpu, the baterry screen comes up, & shows a full charge, then goes to a little cpu w/ cable. my old cable had a bad connection & was making it turn on & off when it was pluged in. got a new cable b/c i thought that was the prob. did i fry it, or can i back it up, & format it.

Re: only turns on when plugged in, dead when unplugged
 

it was the on/off switch, took apart & it wasnt in place, thanks.