$wmiDomain = Get-WmiObject Win32_NTDomain -Filter "DnsForestName = '$( (Get-WmiObject Win32_ComputerSystem).Domain)'"
$domain = $wmiDomain.DomainName
	
PS C:> Get-WmiObject Win32_ComputerSystem

Domain              : WORKGROUP
Manufacturer        : Hewlett-Packard
Model               : HP EliteBook 8530w (XXXXXXXXX)
Name                : ABCHPP2
PrimaryOwnerName    : ABC
TotalPhysicalMemory : 4190388224
	
PS C:> (gwmi WIN32_ComputerSystem).Domain
	
nbtstat -n | Select-String -Pattern "^ *(.*) *<1B>.*$" | % {$_ -replace '^ *(.*) *<1B>.*$','$1'}
	
PS C:> (gwmi Win32_NTDomain).DomainName
	
# Retrieve Distinguished Name of current domain.
$Domain = [System.DirectoryServices.ActiveDirectory.Domain]::GetCurrentDomain()
$Root = $Domain.GetDirectoryEntry()
$Base = ($Root.distinguishedName)

# Use the NameTranslate object.
$objTrans = New-Object -comObject "NameTranslate"
$objNT = $objTrans.GetType()

# Invoke the Init method to Initialize NameTranslate by locating
# the Global Catalog. Note the constant 3 is ADS_NAME_INITTYPE_GC.
$objNT.InvokeMember("Init", "InvokeMethod", $Null, $objTrans, (3, $Null))

# Use the Set method to specify the Distinguished Name of the current domain.
# Note the constant 1 is ADS_NAME_TYPE_1779.
$objNT.InvokeMember("Set", "InvokeMethod", $Null, $objTrans, (1, "$Base"))

# Use the Get method to retrieve the NetBIOS name of the current domain.
# Note the constant 3 is ADS_NAME_TYPE_NT4.
# The value retrieved includes a trailing backslash.
$strDomain = $objNT.InvokeMember("Get", "InvokeMethod", $Null, $objTrans, 3)
	
import-module activedirectory
(Get-ADDomain -Identity (Get-WmiObject Win32_ComputerSystem).Domain).NetBIOSName