How to Find Your Computer Model & Serial Number
If you want to find out the computer model name and the computer serial number of your Windows PC, here is a simple way to do it using the command prompt and HP Support Assistant.
Windows doesn't display your PC's serial number anywhere in its ... the PC manufacturer saved it to your computer's BIOS or UEFI firmware. ...
You’ve got a problem with your computer, you call their technical support team and the person on the other side requires the machine’s serial number (also known as the Service Tag) before he can even log your request.
If you want to purchase any accessory of your pc you have to know that model number and serial number.