Hello Sasan
There are ways.
A good way is create a Windows Service instead of a normal application.
Look at this link:
Creating a Windows Service in C#
Or add your program to Registery:
RegistryKey add = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);
add.SetValue("YourProgram", "\"" + Application.ExecutablePath.ToString() + "\);
Better description, Look at this:
Run the application at Windows startup
Or this:
c# Add application under startup through programme
Or ...
Why don't you search google and find millions links?