sounds like the battery's dead. batteries lose their ability to hold charge after so long. moreso when they're used while plugged in/constantly charging, but can also die with normal usage. there sounds like 2 things are wrong here.
1. there's a loose connection on the board where the charging adapter goes in OR the wires are loose in the actual plug, and
2. the battery can't hold it's charge anymore.
depending on the type of battery it takes, you might be able to replace it. some/most will take rechargeable AA batteries or something, but if you're unlucky, it's battery is like that of a laptop - odd shaped and more expensive to replace than buy a new player.
if the second scenario is the case, and it's battery pack is like that of a laptop (a "pack"), and you feel the need to fix it instead of go and buy a new battery/player, here's what you can do.
them batteries are most like laptop batteries, in that they're packs. or packs of batteries in an odd-shaped housing. pry open the lid of the battery pack and inside will most likely be several smaller battery cells wires/soldered together. they may be typical AA/AAA batteries, in which case you're in luck. count the number of cells in there, and go and buy some replacements of the same size and power (note the "Ah" (Amp-hour) rating on the battery pack), divide that number by the number of cells inside and you got the minimum power requirement for your replacements. when you got some, rip out the old ones and replace them with the new ones in the exact same configuration. re-assemble, and re-charge thoroughly for a minimum of 12 hours (if you can).
if you're feeling really skillful, you can attempt to fix that power connector too, and it'll be good as new =)
Thanks dan, I'll check it out
