Renamed hard disk, but login screen displays old name

[NotATechie]

Nothing disasterous, but vaguely annoying: I've just given my husband my iBook and he wanted to change the hard disk's name. It was easy enough to click on the icon and type the new name, but oddly when he restarts, the old name appears on the login screen, under the apple icon. How can we get the new name to appear there?

Running 10.3.9, G3 iBook with dual usb