Cannot save or cannot keep saved changes.
first implies hardware failure that changing battery wont fix. Second implies dead battery that battery change can fix.
The jumper when changing battery is pointless. You remove old battery, BIOS is powerless and forgets things back to defaults, you put new one back and it's done.
Bios reset jumper on desktops just makes resetting bios easier by skipping the need to take out the battery.