Finding serial number of PC

On windows:
1. On your Windows PC, activate WMIC (Windows Management Instrumentation Command-line). Open the "Start" menu and choose the "Run" option. In the dialogue box that is opened, type "wmic." If this is the first time you have used WMIC, Windows will install it automatically.
2.Type the serial number request into WMIC. When installed, WMIC will display a command prompt, into which various commands can be typed into. The command to retrieve your PC's serial number is "bios get serialnumber."





Reference:
http://www.ehow.com/how_5794011_serial-number-pc-windows.html