• last year
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Cells.Interior.Color = vbWhite

Dim ROW_NUMBER As Integer
Dim COLUMN_NUMBER As Integer

ROW_NUMBER = ActiveCell.Row
COLUMN_NUMBER = ActiveCell.Column

For I = 1 To COLUMN_NUMBER

Cells(ROW_NUMBER, I).Interior.Color = vbBlue
Next I

For J = 1 To ROW_NUMBER

Cells(J, COLUMN_NUMBER).Interior.Color = vbBlue
Next J
End Sub