I'll include the pictures below, the desktop model# is am1100-e1402a
I found this service manual here, couldn't seem to find anything on the battery removal or motherboard.
I can't seem to figure out to remove the cmos battery, it has a plastic housing with 4 plastic tabs holding it down, the hosing appears to be 1 piece with a slot in it for the metal tab, tried pressing the metal tab, it has no play and is being restricted by the plastic housing, also tried seeing if i could wiggle it out of the plastic housing but not enough wiggle room. Not sure if the battery is removable but found other posts of people saying they replaced theirs.
(not sure if the pictures would attach so i included these links just incase)
Any help would be greatly appreciated.