RECALCULATION & RANDOM NUMBERS

DAHOWARDUK  ``Is there a way that I can set Worksheet 2, to only recalculate manually, whilst the remainder of the Workbook, recalculates automatically?``

Yes.  In a new "normal" module (not a worksheet object), enter the following macros.

Sub disableCalc()
ActiveSheet.EnableCalculation = False
MsgBox ActiveSheet.Name & " enabled: " & ActiveSheet.EnableCalculation
End Sub

Sub enableCalc()
ActiveSheet.EnableCalculation = True
MsgBox ActiveSheet.Name & " enabled: " & ActiveSheet.EnableCalculation
End Sub

Sub calcStatus()
MsgBox ActiveSheet.Name & " enabled: " & ActiveSheet.EnableCalculation
End Sub

Sub recalcSheet()
Dim oldcalc As Variant
oldcalc = ActiveSheet.EnableCalculation
ActiveSheet.EnableCalculation = False
ActiveSheet.EnableCalculation = True
ActiveSheet.EnableCalculation = oldcalc
MsgBox ActiveSheet.Name & " enabled: " & ActiveSheet.EnableCalculation
End Sub

In Excel, use alt+f8 to select and run the desired macro.

Also, enter the following Worksheet_Open event macro or add the statement.

Private Sub Workbook_Open()
Sheet2.EnableCalculation = False
End Sub

Note:  You might need to change Sheet2 to the object name (not the worksheet name) of the worksheet with the "frozen" random data.

This is demonstrated in the attached Excel file.

Note: Sheet1 contains one formula (A6) that used RAND() directly.  This is for demonstration purposes only.  Normally, we would put all random data in a separate worksheet, as you indicated.