Блокировка моего программного обеспечения после указанного времени в C#

---

Я написал некоторый код для блокировки моего программного обеспечения после указанного времени. Для этого я использовал реестр.
I created One sub-key and checking there whether my software is running first time or not. If first time then I am creating sub-key and storing installation date.I am reading that date and adding some days and checking every time when user opened my software . Here Everything is working fine but after locked the software if user changes date and restore data then I am unable to track that. So I added other sub-key for that and when ever i am locking software I am replacing that sub-key value with 1.using that I want to check already one time locked software so if he restored data and changed date also I can lock the software. Here only I am getting problem. after locking software system is not adding value to that sub-key and giving error that "cannot write to the registry". So where I did mistake, I am unable to find. I checked net also and I found one post here that telling how to edit values of registry sub-keys. I tried that also but problem not rectified.

Здесь я также публикую свой код

//code to lock software after specified date
            Microsoft.Win32.RegistryKey key = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\OurSettings");
            if (key != null)
            {
                Microsoft.Win32.RegistryKey subkey = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\OurSettings\other");
                if (subkey != null)
                {
                    uncheck();
                }
                else
                {
                    checkService();
                    getipl();
                    crelogin();
                    chklogin();
                    chkpass();
                }
            }
            else
            {
                RegistryKey subkey = Registry.CurrentUser.CreateSubKey(@"SOFTWARE\OurSettings\other");
                MessageBox.Show("Created");
                
                subkey.SetValue("InstallDate", DateTime.Now.ToBinary(), RegistryValueKind.QWord);
                subkey.SetValue("number", cn, RegistryValueKind.QWord);//cn is for checking whether locked or not.cn is public variable declared as public void int cn=0
                subkey.Close();
                uncheck();
            }
            checkService();
            getipl();
            crelogin();
            chklogin();
            chkpass();
        }
        public void uncheck()
        {
            Microsoft.Win32.RegistryKey subkey = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\OurSettings\other");
            try
            {
                var result = (long)subkey.GetValue("InstallDate", "date");
                var date = DateTime.FromBinary(result);
                MessageBox.Show("Install Date" + " " + date.ToString());
                var comp = date.AddDays(30);// locking days after installation.
                var dt = DateTime.Now;
                //var num = (long)key.GetValue("state", "number");
                MessageBox.Show("next Lock Date" + " " + comp.ToString());
                //MessageBox.Show("state"+" "+num.ToString());
                if (date >= comp)
                {
                    Microsoft.Win32.RegistryKey subkey = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\OurSettings\other");
                    con.Close();
                    con.Open();
                    SqlCommand cmd = new SqlCommand("delete  comapny where ctype='b'", con);
                    cmd.ExecuteNonQuery();
                    con.Close();
                    cn = 1;
                    subkey.SetValue("number", cn, RegistryValueKind.QWord);
                    subkey.Close();
                    Form2 frm2 = new Form2();
                    frm2.ShowDialog();//calling other window to show message
                    this.Close();
                }
                else if (dt >= comp)
                {
                    Microsoft.Win32.RegistryKey subkey = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\OurSettings\other");
                    con.Open();
                    SqlCommand cmd = new SqlCommand("delete  comapny where ctype='b'", con);
                    cmd.ExecuteNonQuery();
                    con.Close();
                    //cn = 1;
                    //key.SetValue("number", cn, RegistryValueKind.QWord);
                    //key.Close();
                    Form2 frm2 = new Form2();
                    frm2.ShowDialog();//calling other window to show message
                    this.Close();
                }
                else
                {
                    checkService();
                    getipl();
                    crelogin();
                    chklogin();
                    chkpass();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Software Is Locked. Contact 9290345689");
                this.Close();
            }
        }

Что я уже пробовал:

I checked net also and i found one post here that telling how to edit values of registry sub-keys. I tried that also but problem not rectified.

---