try
<asp:LinkButton ID="LinkButton1" runat="server" OnClick="LinkButton1_Click">Activate</asp:LinkButton>
protected void LinkButton1_Click(object sender, EventArgs e)
{
string constr = "Your connection string";
using (SqlConnection con = new SqlConnection(constr))
{
string sql = "update YourTableName set Status = 'Activated'";
using (SqlCommand cmd = new SqlCommand(sql))
{
con.Open();
cmd.ExecuteNonQuery();
con.Close();
LinkButton1.Text = "Activated";
}
}
}