I have only just brought a sweex clipz mp3 player but i dont know when it is fully charged

Question edited for clarity and throw in a few capital letters.

The internal battery has failed through lack or use, lack of care and not being fully charged. You may be able to replace it.

https://www.google.com/search?q=sweex+clipz+mp3+player+battery+replacement

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Perhaps you thought you were hanging the battery, but the battery already died. So to won't give any power. Try to switch it on while charging and then unplug it. When it switches on, you know the switch is still working. When it dies as soon as you unplug it, your battery must be replaced. (or buy a new MP3 player)

Probably the media player has something faulty..If it's new, send it back and claim another.
If not , remember how did this start..All of a sudden or did you accidentally drop it?

That would depend on the make and model of the player. I know my MP3 player is fully charged when the battery gauge shows all green.

go to the link below and download the user manual in english
the last one is the english one
http://www.sweex.com/en/assortiment/sound-vision/media-players/MP300110/handleidingen/

Full charge player's battery. Now you must set the power switch to ON position and next hold on the play-pause button for 2-3 seconds. Repeat this step for soft-OFF.
Petr

My Sweex Vidi MP4 Player blu 4GB has stopped

My Sweex Vidi MP4 Player 4GB has stopped working. won't turn on and when connected to PC the PC says nothing

Nightmare product bought for mothers day... doesnt work

It needed to use windows media player and had to sync with that alls working well.

once your mp3 player gets fully charged you can see in the screen of your mp3 player showing "full" near the battery symbol.