删除注册表健值报错，急

RegistryKey   mykey   =Registry.LocalMachine.OpenSubKey(@"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion",true);   
                                RegistryKey   mykeydel   =   mykey.OpenSubKey("Run"); 
                          
                                string   strname   =   "StartCopy"; 

                                mykeydel.DeleteValue(strname); 
报错！“未将对象的引用设置到对象的实例”！  --------------------编程问答-------------------- 用了Registry.LocalMachine，就不要用HKEY_LOCAL_MACHINE\ --------------------编程问答--------------------

RegistryKey   mykeydel   =   mykey.OpenSubKey("Run"); //要改成可写的，mykey.OpenSubKey("Run",true)

--------------------编程问答--------------------

RegistryKey mykey  =Registry.LocalMachine.OpenSubKey("SOFTWARE\Microsoft\Windows\CurrentVersion",true);       

RegistryKey  mykeydel=mykey.OpenSubKey("Run",true);

                                                    

string strname="StartCopy";   



mykeydel.DeleteValue(strname);

--------------------编程问答-------------------- 谢谢 --------------------编程问答--------------------

RegistryKey r = Registry.LocalMachine.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion",true);

                RegistryKey aimdir = r.OpenSubKey("Run", true);

                string[] aimnames = aimdir.GetValueNames();

                foreach (string aimKey in aimnames)

                {

                    if (aimKey == "StartCopy")

                        aimdir.DeleteValue("StartCopy");

                }

补充：.NET技术 ,  C#