Filename = Cell Contents

I would like to modify the below so that the contents of cell D2 of the current file becomes the file name.
Thanks for any help

Phil

Sub FlattenSS()
'
' FlattenSS Macro
'
''
    ActiveSheet.Select
    ActiveSheet.Copy
    ActiveSheet.Unprotect
    Cells.Select
    Selection.Copy
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
        :=False, Transpose:=False
    Range("A1").Select
    Application.CutCopyMode = False
    ActiveSheet.Protect DrawingObjects:=True, Contents:=True, Scenarios:=True
 
    ChDir "C:\Documents and Settings\philip.marshall\Desktop"
    fileSaveName = Application.GetSaveAsFilename( _
    fileFilter:="Excel Files (*.xls), *.xls")
    If fileSaveName <> False Then
    MsgBox "Save as " & fileSaveName
    End If
    
    
End Sub