Fill empty cells with a 0

This code goes in a standard module (ALt+F11) then right click in the VBA project window top left hand side and choose Insert, Module then paste the code below:

Sub Fill_Blanks()
Dim MyCell As Range
For Each MyCell In Range(Selection.Address)
If MyCell = vbNullString Then
MyCell.Value = 0
End If
Next
End Sub

now all you need to do is hilight the range that contains the blanks and data and run the code all empty cells will now have a 0.