Laptop battery won't charge

[Abigail]

The battery for my laptop won't charge. It's about 8 months old so I don't think its the age. The battery light flashes orange four times then green once. I've had it charging all night and today but it's still on 0% power. I've looked at the control pannel for the battery and it just says it's online, it doesn't say if it's discharging or charging.
I've just swapped the batteries over and the other battery is charging on a solid green light.

The laptop works fine when it's pluged into the mains. I do have another battery so it's not a major problem but I'm a bit peeved as it cost £60.
The battery that won't charge is a 6 cell and the other one is a 4 cell if that helps.

What can I do?

[Kim]

I don't think there's anything you can do. We've hardly used the battery on my dad's laptop and it had been plugged in constantly, but when I went to take the laptop outside, it said it was on 45% even though I'd only just gone outside.

Is your warranty only a 6 month one then, because that's what my mate's was.