Symptom
You need locate your system’s service tag (also referred to as the serial number) using Command Prompt.
Resolutions
Type cmd in the Windows search bar at the bottom-left of the screen, then select Command Prompt from the list of results.
In the Command Prompt window, type wmic bios get serialnumber and press Enter.
The Service Tag (Serial Number) appears as shown in the image below.
 using Command Prompt.){kind=link}