For whatever reason, you might need to use your computer’s serial number. That is not something you are generally expected to keep in your head, so you will have to check on your computer. Often it is written on a sticker located on the underside of the computer or within the battery compartment, but sometimes the writings are not legible; especially if it is an old computer.
If that’s you right now, scratching your head thinking of how to find your computer serial number. Worry not! You don’t have to go looking for your box and user manuals that came with your computer. It would be a great inconvenience if you are traveling or away from home.
#1 – Find your Computer Serial Number under the Command Prompt
Press Windows Key/Start Key + R, type in ‘cmd’ and then hit enter. The Command Prompt (CMD) Window will pop up. Type in the following command ‘wmic bios get serialnumber’ and hit enter.
You should have your serial number displayed. If you don’t see the serial number and instead something like ‘0′ or ‘To be filled by O.E.M’, it will mean …read more
Read more here:: How to find your Computer Serial Number [Windows PCs]