please can someone help. i have discovered by battery in my laptop will only charge when i turn on the laptop  by battery power, when i plug it in and turn it on it says battery is not charging..!! iss it the battery fault or the laptop. the battery is only 1 year old and not often used on its own

thank you would apreciate your thoughts as i have a charilty dance to run and need my battery as its outside and i need my music..gq