No-one likes rearranging their desk to find the little white sticker. It can be run from regular command or PowerShell session. Administrator permissions aren’t required.

Here is how to find it via Windows:

Command Prompt

wmic bios get serialnumber

Powershell

(Get-WmiObject win32_bios).SerialNumber

Powershell (Remote Computer)

(Get-WmiObject win32_bios -computer COMPUTERNAME).SerialNumber