HP ProDesk 400 G2 Small Form Factor Maintenance And Service Manual page 140

NOTE:
8. Replace the access panel.
9. Plug in the computer and turn on power to the computer.
10. Reset the date and time, your passwords, and any special system setups using Computer Setup.
11. Lock any security devices that were disengaged when the access panel was removed.
132 Appendix A Battery replacement
After the battery has been replaced, use the following steps to complete this procedure.