Welcome to the forum Daeran. Try plugging it into a PC for several hours before using the regular power supply. Make sure the PC doesn't sleep during this period. If it still doesn't charge, it does seem as if you have a defective battery. I don't know if it's possible, but if it doesn't work properly, can you ask the person who gave it to you where he/she got it, and if it's possible to return it for one that works?