Forgot Active Directory Password Script in .NET
Private Function ChangeLocalUserPassword(ByVal User As String, ByVal Pass As String) As Boolean
    Dim pinger As New Net.NetworkInformation.Ping
    Dim usr As DirectoryEntry
    _de = GetDirectoryEntry()

    If _de Is Nothing Then
        'couldn't connect or find account
        MsgBox("_de is Nothing")
        Return False
    End If
    Try
        usr = _de.Children.Find("CN=" & User, "User")
    Catch ex As Exception
        MsgBox("User could not be found!")
        Return False
    End Try
    Try
        usr.Invoke("SetPassword", Pass)
        usr.CommitChanges()
        usr.Properties("LockOutTime").Value = 0
        usr.CommitChanges()
    Catch ex As Exception
        MsgBox("Error is " & ex.Message)
        Return False
    End Try

End Function

Private Function GetDirectoryEntry() As DirectoryEntry
        Dim dirEntry As DirectoryEntry = New DirectoryEntry()
        dirEntry.Path = "LDAP://<SERVER>/ou=<OU>,dc=<DOMAIN>"
        dirEntry.Username = "<DOMAIN>Administrator"
        dirEntry.Password = "<PASSWORD>"
        Return dirEntry
    End Function