Convert number to text

I am trying to create a Macro to convert a number to text. I have the following code:
Sub Convert2Text()

For Each Cell In Selection.Cells

OldNF$ = Cell.NumberFormat

Cell.NumberFormat = "@"

Cell.Value = Application.Text(Cell.Value, OldNF$)

Next

End Sub
This works great until I get to a cell with a blank value, then it returns a 0. I need it to leave the cell blank. I am very new at scripting but I was thinking some type of a condition loop applied to the above logic might work. Any help would be great. Thanks.