The charger cord is the same cord the laptop itself uses. It should charge the battery. Unless either the battery has gone bad, the charging circuit is bad or the charger cord is going bad, it should get charged.
Try charging it when the laptop is turned off. If it will charge when turned off (not hibernate or sleep, but off) however won't charge when on, then the charger is the problem. There is no way to fix it, so it would need to be replaced.
If, however, if won't charge even when turned off, then you are looking at either a battery replacement or the charging circuit (and possibly the motherboard) will need replacing.