My battery doesnt seem to be holding a charge anymore. I can charge it fine with my pc and the wall adapter and it shows it's fully charged because the little battery stops moving. But when I disconnect it I see the battery go down in a matter of seconds when theres something on the screen. I know im charging it right and I use the pause button for on and off, it also just started today. Should I try and see if I could buy a new battery or would FW do the trick because the battery isnt old. Please help.

How long have you had your player now?
How often have you been charging it?
It's been recommended for the first 5 charges, to let the battery run down completely then do a full, overnight charge instead of doing little charges here and there.......

I haven't replaced a battery myself personally, so not entirely sure what's involved. A firmware update is not necessary, it will probably cause you MORE problems.