Sub Beispiel()
Dim Spalte As Integer
Dim Zelle As Long
For Spalte = 1 To Cells.SpecialCells(xlCellTypeLastCell).Column 'max. 256
 For Zelle = 1 To Cells(Rows.Count, Spalte).End(xlDown).Row
    If Cells(Zelle, Spalte).Value = "3" Then
     MsgBox "Bedingung erfüllt!", 64, Cells(Zelle, Spalte).Address
    End If
 Next Zelle
Next Spalte
End Sub