Salut Mahadey
Mettez ce code dans le bouton Valider
Private Sub CommandButton1_Click()
Dim iRow As Integer, iCol As Integer
iRow = Val(ComboBox1.ListIndex) + 2
iCol = Val(ComboBox2.ListIndex) + 2
If iRow = 1 Or iCol = 1 Then Exit Sub
Cells(iRow, iCol).Value = Me.TextBox1.Value
End Sub