Option Explicit
Private Sub Worksheet_SelectionChange(ByVal c As Range)
Application.ScreenUpdating = False
ActiveSheet.UsedRange.Interior.ColorIndex = xlNone
For Each c In ActiveSheet.UsedRange
If c.Value <> 0 Or Not IsNumeric(c) Then c.Interior.ColorIndex = 38 Else c.Interior.ColorIndex = xlNone
Next
Application.ScreenUpdating = True
End Sub