If you're like me and need to name a new HP-computer, you're using the serial number as the computer name and maybe add a prefix to differentiate between locations etc; eg SRV-4CZ2435TUI or CLI-4CZ2435TUI.
So, you then need to find out the HP-computer's serial number. If you also are too lazy to flip the notebook over and read out dark-gray on black(...) fine-printed text, here's a better way.
Open a command prompt or terminal and type the below.
c:\ >wmic bios get serialnumber
$ dmidecode | grep 'SKU Number' | head -1
SKU Number: 4CZ2435TUI