MacBook Air slow & jerky response and doesn't charge battery.

My MacBook Air OS X version 10.8.5 , processor 1.8 GHz Intel Core 15, 4GB 1600 MHz DR3 quit charging the battery and now it is very slow to respond and when it finally does, it's jerky. Tried resetting SMC and PRAM. Didn't help. Power cord works although light isn't lite. Battery charge is zero. Any suggestions?