Bulk Rename AD Computers by Serial Number

<#
.SYNOPSIS
    Bulk rename AD computers using their hardware serial number.
.DESCRIPTION
    Queries each computer in the target OU for its BIOS serial number,
    then renames the AD object to a standardised format.
.PARAMETER OUPath
    Distinguished name of the OU containing target computers.
.PARAMETER Prefix
    Naming prefix, e.g. "WS-" for workstations or "LT-" for laptops.
.PARAMETER WhatIf
    Preview changes without applying them.
#>

param(
    [Parameter(Mandatory)]
    [string]$OUPath,

    [string]$Prefix = "WS-",

    [switch]$WhatIf
)

Import-Module ActiveDirectory -ErrorAction Stop

$computers = Get-ADComputer -Filter * -SearchBase $OUPath -Properties Name, DNSHostName

foreach ($computer in $computers) {
    try {
        # Query the serial number from the remote machine
        $serial = (Get-CimInstance -ClassName Win32_BIOS -ComputerName $computer.DNSHostName -ErrorAction Stop).SerialNumber

        if ([string]::IsNullOrWhiteSpace($serial) -or $serial -eq "To Be Filled By O.E.M.") {
            Write-Warning "Skipping $($computer.Name): no valid serial number found."
            continue
        }

        # Clean the serial — remove spaces and special characters
        $cleanSerial = ($serial -replace '[^a-zA-Z0-9]', '').ToUpper()
        $newName = "$Prefix$cleanSerial"

        # Truncate to 15 characters (NetBIOS limit)
        if ($newName.Length -gt 15) {
            $newName = $newName.Substring(0, 15)
        }

        if ($computer.Name -eq $newName) {
            Write-Host "SKIP $($computer.Name) — already named correctly." -ForegroundColor Gray
            continue
        }

        if ($WhatIf) {
            Write-Host "WHATIF: Would rename $($computer.Name) -> $newName" -ForegroundColor Cyan
        } else {
            Rename-ADObject -Identity $computer.DistinguishedName -NewName $newName
            Set-ADComputer -Identity $computer.DistinguishedName -SAMAccountName "$newName$"
            Write-Host "RENAMED $($computer.Name) -> $newName" -ForegroundColor Green
        }
    } catch {
        Write-Warning "ERROR on $($computer.Name): $_"
    }
}

.\Rename-ComputersBySerial.ps1 -OUPath "OU=Workstations,DC=corp,DC=cyberitex,DC=com" -Prefix "WS-" -WhatIf

.\Rename-ComputersBySerial.ps1 -OUPath "OU=Workstations,DC=corp,DC=cyberitex,DC=com" -Prefix "WS-"

.\Rename-ComputersBySerial.ps1 -OUPath "OU=Laptops,DC=corp,DC=cyberitex,DC=com" -Prefix "LT-"