Executing a method only once in windows form app in c#

Hi Paras,
In Programm class (Start up Class) and within the static method try to check the data is exist in registry or not. if not exist then call your method, and if not exist then call the your method.

Code 
string filename;
string KeyName="your registry key name where your text exist";
// Opening the registry key 

RegistryKey rk = baseRegistryKey ; 

// Open a subKey as read-only 

RegistryKey sk1 = rk.OpenSubKey(subKey); 

// If the RegistrySubKey doesn't exist -> (null) 

if ( sk1 == null ) 
{ 

          //Call Method
} 

else 
{ 

        try 
        { 

                // If the RegistryKey exists I get its value // or null is returned. 

                filename= (string)sk1.GetValue(KeyName.ToUpper()); 
        } 

        catch (Exception e) 
        { 

                // AAAAAAAAAAARGH, an error! 

                MessageBox.Show(e, "Reading registry " + KeyName.ToUpper());
        } 
} 

if(File.Exists("full path")==true)
{
         MessageBox.Show("File Exists");
}
else
{
       MessageBox.Show("File not Exists");
}
Kindly mark as answer , if it helps to you
Thanks,
Kailash

Sir i want to write data in registry only once.So i made a method of writing data in it,now i want to call this method only once in my application.

Hi Paras,
Can you explain your requirement with conditions you want implement.
Thanks
Kailash