charging problems...

this might be a simple problem but the battery icon on the top right of my screen has a cross in it and when i unplug my charger my computer turns off. Basically i cant charge it. the light on the charger plug is green.
whats wrong?

thanks.

try shutting down, then pulling the battery and unplugging.
then hold the power button down for about 10 sec.
replace the battery and power and restart.

see if you get a normal battery icon.

if that doesn't work, it could be your battery or power unit (inside the macbook). if you have another macbook (a friend's) you could try to swap batteries and see if the problem follows your macbook or the battery.