Private Sub Command1_Click()
 Dim Num As String
 Dim Cuenta As Byte
 
 Text1 = ""
 Math.Randomize
 
 Do While Not Cuenta = 26
    Num = Int(Rnd * 26)
    Cuenta = Cuenta + 1
    Select Case Num
        Case "0"
            Num = "A"
        Case "1"
            Num = "B"
        Case "2"
            Num = "C"
        Case "3"
            Num = "D"
        '...
    End Select
    Text1 = Text1 & Num
Loop
End Sub

Option Explicit
Option Base 1

Const SORT_ASC = 1
Const SORT_DES = 2
Const SORT_RAND = 3

Function SortAbc(SortMode As Integer) As String
        Dim iChar() As Byte
        Dim bExist  As Boolean
        Dim i%, ind%, iRnd%
        Dim sData$

  ReDim Preserve iChar(0 To (vbKeyZ - vbKeyA)) As Byte

  Call Randomize(vbKeyZ)

  For i = vbKeyA To vbKeyZ
    Select Case SortMode
      Case SORT_DES
        sData = sData & Chr$((vbKeyZ - i) + vbKeyA)
      Case SORT_ASC
        sData = sData & Chr$(i)
      Case SORT_RAND
NewNum:
        iRnd = Rnd * vbKeyZ
       
        If iRnd < vbKeyA Then GoTo NewNum
       
        For ind = 1 To (vbKeyZ - vbKeyA)
          If iChar(ind) = iRnd Then
            bExist = True
            Exit For
          End If
        Next
       
        If ind >= 25 Then bExist = False
       
        If bExist Then GoTo NewNum
       
        iChar(i - vbKeyA) = iRnd
        sData = sData & Chr$(iChar(i - vbKeyA))
       
    End Select
  Next

  SortAbc = sData
End Function