The A3000 is the same as the 4000, you have to remove the motherboard and desolder the battery from underneath (the "legs" are welded to the battery, it's not in a holder). If you're worried about corrosion and can't desolder the battery yourself another option is to clip the "legs" with a pair of snips. Then when you can get it into the shop a technician can remove the stubs left behind and put in a new battery.
The computer will run fine without at battery BTW.
HTH
Robert
