$sn = Get-WmiObject -Class Win32_bios | Select-Object -ExpandProperty serialNumber
$computer = $env:COMPUTERNAME
Set-ADComputer -Identity $computer -Replace @{serialNumber = $sn } -ErrorAction SilentlyContinue -ErrorVariable $serialAddErr -WarningVariable $serialAddEWarn
$serialAddErr | Out-File -FilePath c:\serialAddErr.txt -Append
$serialAddEWarn | Out-File -FilePath c:\serialAddErr.txt -Append