Here is simple random password generator:

Use it following way:

Dim Password As String = String.Format("{0}{1}{2}", GRP(CharType.SpecialCharacters, 2), _
GRP(CharType.Numbers, 2), GRP(CharType.UpperCase, 2))

Private Function GRP(ByVal StringType As CharType, ByVal Length As Integer) As String

        Dim FindForm As String = ""

        Select Case StringType

            Case CharType.UpperCase

                FindForm = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

            Case CharType.LowerCase

                FindForm = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

            Case CharType.Numbers

                FindForm = "0123456789"

            Case CharType.SpecialCharacters

                FindForm = "!@#$%^&*"

        End Select

        Dim rand = New Random()

        Dim randomstr = Enumerable.Repeat(0, Length).Select(Function(f) FindForm(rand.Next(0, FindForm.Length)))

        Return String.Concat(randomstr.ToArray)

    End Function

    Enum CharType

        UpperCase

        LowerCase

        Numbers

        SpecialCharacters

    End Enum