Sony VAIO VGN-FW300 - Manual (Page 22)

22 n N
Getting Started
3 Slide the battery pack diagonally into the battery compartment until the projections (2) on either side of the battery
compartment fit into the U-shaped cuts (3) on either side of the battery pack.
4 Push the battery pack down into the compartment until it clicks into place.
5 Slide the battery LOCK switch outward to secure the battery pack on the computer.