Finding Average of 3 Numbers excluding zeros

[DataMiser]

You may want to try somethign more like this

If Val(txtValueA.Text) = 0 Then
    If Val(txtValueB.Text) = 0 Then
        If Val(txtValueC.Text) = 0 Then
            'No Valid entries above 0
            txtAverage.Text ="0"
        Else
            txtAverage.Text = Val(txtValueC.Text)
        End If
    Else
        If Val(txtValueC.Text) = 0 Then
            'Only b is valid
            txtAverage.Text = Val(txtValueB.Text)
        Else 'B and C are valid
            txtAverage.Text = Round(((Val(txtValueB.Text) + Val(txtValueC.Text)) / 2), 2)
        End If
    End If
Else
    If Val(txtValueB.Text) = 0 Then
        If Val(txtValueC.Text) = 0 Then
            'Only A is valid
            txtAverage.Text = Val(txtValueA.Text)
        Else 'Only A and C are valid
            txtAverage.Text = Round(((Val(txtValueA.Text) + Val(txtValueC.Text)) / 2), 2)
        End If
    Else
        If Val(txtValueC.Text) = 0 Then
            'Only a and b are valid
            txtAverage.Text = Round(((Val(txtValueB.Text) + Val(txtValueB.Text)) / 2), 2)
        Else ' all are valid
            txtAverage.Text = Round(((Val(txtValueA.Text) + Val(txtValueB.Text) + Val(txtValueC.Text)) / 3), 2)
        End If
    End If
End If

Edit: Never mind, the post above is a better way to go.
You still may want to look over the If structure in this post though to get an idea of the logic