HP ProBook 455 G1 Notebook PC - Manual (Page 53)

3. Connect the AC adapter to the computer, and then plug it into an AC outlet.
4. Turn on the computer.
● If the power lights turn on, the AC adapter is working properly.
● If the power lights remain off, the AC adapter is not functioning and should be replaced.
Contact support for information on obtaining a replacement AC power adapter.
Setting power options 43