My mp3 media player will not turn on.

That little led is a battery 's warning,when green the battery is fully charged,when yellow or orange the battery is half way or so and tells you to charge it pretty soon,once the led goes red then the screen becomes black because no much power.
when you charge the Mp3 the display stays on at all the time,it is not an issue or a problem. Hope i understood what you want to know and if you still need help ,please explain it better in the reply!
thank you,
Cris,the best you can find on Fixya

charge it via the computer

try taking out the battery if it has or push the on/off button for a long time

I PLUGGED IN MY MP3 PLAYER TO THE COMPUTER AND THE SCREEN ON MY MP3 PLAYER LIGHTS UP BUT the normal screen image for when you normally plug it into the computer ISN'T THERE AND I CAN'T ADD MUSIC ON MY MP3 PLAYER.

You need to turn on your mp3 and press connect to computer then the computer will verify it.

i would get a new charger and go from there

listening to music when it suddenly turns off. it doesnt wanna turn on. tried charging it but it does nothing. its just a black screen. ..help?

Charge it...

Did you charge the unit over night? When they are brand new, the batteries are not always charged. See if the lights and screen come on when it is plugged into the charger. If so let it charge over night and try turning it on again. Otherwise, you should probably return the unit.

Only 2 suggestions here: 1) Make sure your HOLD switch is not enabled. 2) Try to update the firmware If neither of these work, time to send the unit back to Sandisk