Private Declare Function GetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, nSize As Long) As Long

Declare Function LookupAccountName Lib "advapi32.dll" Alias "LookupAccountNameA" (lpSystemName As String, ByVal lpAccountName As String, sid As Any, cbSid As Long, ByVal ReferencedDomainName As String, cbReferencedDomainName As Long, peUse As Long) As Long

Private Sub Form_Load()
     Dim sDomainName As String * 255
     Dim lDomainNameLength As Long
     Dim sUserName As String
     Dim bUserSid(255) As Byte
     Dim lSIDType As Long

    ' Create a buffer
    sUserName = String(100, Chr$(0))

    ' Get the username
     GetUserName sUserName, 100

    'strip the rest of the buffer
    sUserName = Left$(sUserName, InStr(sUserName, Chr$(0)) - 1)

     ' Show the temppath and the username
     MsgBox "Hello " + strUserName

     lResult = LookupAccountName(vbNullString, sUserName, bUserSid(0), 255, sDomainName, lDomainNameLength, _
  lSIDType)
    If lResult <> 0 Then
       MsgBox sDomainName
    End If
End Sub