Excel Form (VBA) validation help needed urgently

Hello all, Im customising some code I got online at the page http://www.contextures.com/xlForm02.html
I need some help editing the code in red. Basically, the code is used in conjunction with an excel form, so the user form is on one worksheet and the data collected is stored in another sheet. Currently there's a validation check to ensure that all cells have data entered. I want to adjust it since there are specific cells I wont need data in. So i figure the key piece of code is the line

 If Application.CountA(myRng) <> myRng.Cells.Count

so i want to adjust it to something like If Application.CountA(myRng) <> myRng.Cells.Count excluding cell D13. Im just not sure of the correct syntax. Hope i was clear enough. Thank you all in advance for your speedy responses.

Dim historyWks As Worksheet
    Dim inputWks As Worksheet

    Dim nextRow As Long
    Dim oCol As Long

    Dim myRng As Range
    Dim myCopy As String
    Dim myCell As Range
    
    'cells to copy from Input sheet - some contain formulas
    myCopy = "D5,D7,D9,D11,D13"

    Set inputWks = Worksheets("Input")
    Set historyWks = Worksheets("PartsData")

    With historyWks
        nextRow = .Cells(.Rows.Count, "A").End(xlUp).Offset(1, 0).Row
    End With

    With inputWks
        Set myRng = .Range(myCopy)

        If Application.CountA(myRng) <> myRng.Cells.Count Then
            MsgBox "Please fill in all the cells!"
            Exit Sub
        End If
    End With

    
        For Each myCell In myRng.Cells
            historyWks.Cells(nextRow, oCol).Value = myCell.Value
            oCol = oCol + 1
        Next myCell
    End With

You should be able to use:

If myRng.Count <> Application.WorksheetFunction.CountA(myRng) then

Oh, if you want to remove D13, take it out of your line "myCopy = "D5,D7,D9,D11,D13"" change to myCopy = "D5,D7,D9,D11"

Thanks Blobbles, i'll try it

ok im still having a problem, this one may not be restricted to the validation.

im getting an "Application Defined or Object Defined Error" error at line this line

 historyWks.Cells(nextRow, oCol).Value = myCell.Value

So basically, the code is supposed to get the data in the MyCopy cells on the input sheet, then copy the contents to the salesdata sheet. on the sales data sheet, its supposed to start inputting the contents that were copied into cell D3, contiguously within that sheet. so it would just paste into cell D3,E3,F3,H3 Etc etc.I think i may have some syntax errors. Can anyone assist??
again, a link to the original sample code i got online is at:
http://www.contextures.com/xlForm02.html#edit

Option Explicit

Sub UpdateLogWorksheet()

    Dim historyWks As Worksheet
    Dim inputWks As Worksheet

    Dim nextRow As Long
    Dim oCol As Long

    Dim myRng As Range
    Dim myCopy As String
    Dim myCell As Range
    
    'cells to copy from Input sheet - some contain formulas
    myCopy = "D7,D9,D11,D13,I7,I9,I11,I13,N7,N9,N11,N13"

    Set inputWks = Worksheets("Input")
    Set historyWks = Worksheets("SalesData")

    With historyWks
        nextRow = .Cells(.Rows.Count, "3,2").End(xlUp).Offset(2, 1).Row
    End With

    With inputWks
        Set myRng = .Range(myCopy)
    
      '  If myRng.Count <> Application.WorksheetFunction.CountA(myRng) Then
            If Application.CountA(myRng) <> myRng.Cells.Count Then
            MsgBox " Please fill out all the cells "
            Exit Sub
        End If
    End With

    With historyWks
            With .Cells(nextRow, "3,2")
            'was b3
            End With
        
        For Each myCell In myRng.Cells
            historyWks.Cells(nextRow, oCol).Value = myCell.Value
            oCol = oCol + 1
        Next myCell
    End With
    
    'clear input cells that contain constants
    With inputWks
      On Error Resume Next
         With .Range(myCopy).Cells.SpecialCells(xlCellTypeConstants)
              .ClearContents
              Application.GoTo .Cells(1) ', Scroll:=True
         End With
      On Error GoTo 0
    End With
End Sub

You pretty much need to upload the sheet with all sensitive information taken out. There could be lots of reasons for this...

humm, but thats the entire code their i've posted

OK, its because you haven't defined the value of oCol. As such it tries to paste the data to column 0, which doesn't exist of course!

...

        oCol = 1
        
        For Each myCell In myRng.Cells
            historyWks.Cells(nextRow, oCol).Value = myCell.Value
            oCol = oCol + 1
        Next myCell

...

thanks for the help Blobbles! that did the trick. have a great day!