Here is a simple way you can tell if its either your laptop battery or your charger. Since it was charging before we can rule out that it is indeed not the laptop.
Take out the laptop battery and plug in the charger. Try turning it on. If it doesn't work then your charger is dead. If it does work then your battery is dead. Also, if you wiggle the charger area thats connected to your laptop and it works, then it means your DC jack is loose.
I had a similar issue and it turned out to be a dead charger. A friend recommended me to a store online that sells laptop chargers with free shipping and lifetime warranties on all their products. If you aren't happy within the first 30 days with it you can send it back to get a full refund.
Hope this helps: http://www.topmic.com/