Laptop won't use battery

Hi all Ok, so here's the problem.... I have a Hp mini 1101 ...netbook...or maybe a notebook, sorry, it was a used gift from my mom, and I don't know much about it.. but my problem is when I first got it, it would work for hours on the battery, now as soon as I unplug it, it cuts off...

It used to charge when plugged up, but... I don't know - now it says the battery is 100% but, it won't switch over What do I need to do so I can unplug it and use it?

The only thing I can really say about the laptop is what it says on it- which is "intel Atom inside" and "HP mini 1101" oh, and I've had it for about 17 months, could it be it needs a new battery? Because like I said, it used to charge up... and it says it's at 100%, but it just won't work unless plugged in. Oh, and the little icon where it used to show a battery, now only shows a plug, and when I click on it, it says "AC power"... don't know if that matters, but I'm just trying to give enough info...

Thanks anyone who has an idea - oh, and I need steps, b/c I am NOT good at computers.

First thought is your battery is shot. Only option is to try and replace it first. Do yourself a favor and order it from Amazon. Way cheaper than a computer store or HP. You may also find there may be a charging circuit issue in the notebook itself. Not that common though.

I'm having the exact same problem. Did you find a solution? Since the battery is showing 100%, I'm hesitant to purchase a new battery. It would seem if the battery shows a charge of 100%, we may just need to change a setting in the computer to make it look to the battery for power.