HP Pavilion g6 Laptop (Ashtead, Surrey.)

Laptop has an Intel i5 Processor and 6GB Ram. 650GB HDD. Running Windows 10 with Microsoft Office 2007 installed. Has not been used for a while but have ensured all Windows upgrades have been installed. Have discovered that although Windows says Battery is 100% when power lead is disconnected the laptop dies. Faulty battery perhaps. A new battery is c.£26 (Amazon). Works 100% on mains power. Would be ideal for child's homework, internet etc. but not powerful enough for detailed games.