Get System ( Desktop / Laptop ) Information

Open the command prompt (windows + R and type cmd) on windows.
The basic command in wmic.

Serial Number

> wmic bios get serialnumber

O/P

SerialNumber

XNNXXXX

Product Id

> wmic os get "SerialNumber"

O/P

SerialNumber
NNNNN-NNN-NNNNNNN-NNNNN

More Info

> wmic computersystem get model,name,manufacturer,systemtype

you can match different options and get more inofrmation.