Check the sticker on the bottom of the laptop
Check under the battery if the battery is removable
Open System Information on Windows and look for Serial Number
Use Command Prompt and run `wmic bios get serialnumber`
Use PowerShell and run `Get-CimInstance Win32_BIOS | Select-Object SerialNumber`
Check the BIOS or UEFI setup screen
Check the original box or purchase receipt
Check the manufacturer’s support app or website
Check the laptop’s warranty or registration details
Contact the manufacturer’s support team