How to save user select item?

i have a form . In that form there are there button and there code is

private void Button1_Click(object sender, EventArgs e)
        {
            ///When this is clicked the form look changes to MS Office 2007 Black  this is default look of my form.
            kryptonManager.GlobalPaletteMode = PaletteModeManager.Office2007Black;
        }

        private void Button2_Click(object sender, EventArgs e)
        {
            ///When this is clicked the form look changes to MS Office 2007 Blue .
            kryptonManager.GlobalPaletteMode = PaletteModeManager.Office2007Blue;
        }

        private void Button3_Click(object sender, EventArgs e)
        {
           ///When this is clicked the form look changes to MS Office 2007 Silver .
            kryptonManager.GlobalPaletteMode = PaletteModeManager.Office2007Silver;
        }

The problem is suppose user click  "Button2" then form look goes "MS Office 2007 Blue" and it works well. But when the user open the same form again its comes to it default look "MS Office 2007 Black" I want code to save the user setting and i am new to C# so plz answer step by step.