Could someone here help me with my Netbook's battery problem??

Whenever I plug the charger in, the thing charges a little bit (for about 5 seconds) then stops. WTF. The charger has always worked fine before today, I don't get what the deal is. Sometimes it gets back to charging about 15 minutes later but then just does the same thing it did before with little or no increase (and sometimes a decrease) in the battery life percentage. What's up here? Does the charger/battery need to be replaced? If so where do I get a new battery (I know where to get a charger) By the way, it is an Acer Netbook and runs Windows 7 if that's of any importance. And if it is the battery that's the problem, how do you replace the battery? Please help!!

 

some the contacts are very thin.. it may be loose, wiggle plug. mine did this brand new out the box..

 

What are contacts??