I want to make a code that check in a range of cells if the number entered by
the user is greater that 0, turn that cell in red and send a message to the
user. I tried this code but not work for me.

Dim rng As Range

Set rng = Range("$B$5:$B$11")

If rng 0 Then
MessageBox.Show ("You have an Alert!")
With Selection.Interior
.ColorIndex = 3
.Pattern = xlSolid
End With
End If

End Sub