Check the sticker on the bottom of the laptop
Check the battery compartment if the battery is removable
Check the original box or purchase receipt
Open System Information on Windows and look for the serial number
Open Command Prompt and run `wmic bios get serialnumber`
Open PowerShell and run `Get-CimInstance Win32_BIOS | Select-Object SerialNumber`
Check BIOS or UEFI settings during startup
Check the manufacturer’s support app or utility
Check the manufacturer’s website using your device account
Contact the laptop manufacturer’s support team