Dell Inspiron 1428 (Late 2009) - Manual (Page 11)

Before You Begin 11
6 Disconnect your computer and all attached devices from their electrical
outlets.
CAUTION: To help prevent damage to the system board, remove the main battery
(see "Removing the Battery" on page 13) before working inside the computer.
7 Remove the battery (see "Removing the Battery" on page 13).
8 Turn the computer top-side up, open the display, and press the power
button to ground the system board.