If you have got MS Configuration Manager running in your setup, you can use it to fetch serial number of a computer.
In addition to the Serial Number, you can get many other details via the SCCM console.
- Open the Configuration Manager console.
- Go to Assets & Compliance > Devices.
- Select a device and right click device, and click Start > Resource Explorer.
- Expand Hardware > PC BIOS. Look for the serial number column.
- Note down the serial number of the computer.