VBA For loop

[iamGreenhorn]

I need a little help getting in the right direction and I should be fine from there.

So the background here is i have a huge 10K line data file I need to search through and find up to three unique results given two conditions. the first condition has a possible of 93 outcomes and the second condition has a possible of 5 outcomes; for a total of about 10k random entries. I want to grow this function to fill lots of data but I keep getting random issues. consistently "error 1004".

This 10k file is updated constantly and i need to create reports for every year in the future so you're help here is really appreciated.

Private Sub CommandButton3_Click()
    Dim LastRow As String
    Dim z As Integer
    Dim CellOne As String
    Dim CellTwo As String
    Dim CellThree As String
    
    'get the row count for the loop
    Sheets("2015 DATA").Select
    LastRow = Cells(Rows.Count, "A").End(xlUp).Row

    'now we loop, match all countries and classes and output the factories
         CellOne = None
         CellTwo = None
         CellThree = None
    
        Sheets("2015 DATA").Select
        Range("A1").Select
        
    For z = 1 To LastRow
    If Worksheets("2015 DATA").Cells(z, 9).Value = "CO" And Worksheets("2015 DATA").Cells(z, 27).Value = "class 12" Then
    
    If CellOne = None Then CellOne = Worksheets("2015 DATA").Cells(z, 7).Value
    If CellTwo = None Then CellOne = Worksheets("2015 DATA").Cells(z, 7).Value
    If CellThree = None Then CellOne = Worksheets("2015 DATA").Cells(z, 7).Value
    
    End If

    Next z
    
      MsgBox (CellOne & CellTwo & CellThree)
End Sub