Well, you've got 2 options really :

  • Finding out what version of windows the user has, then finding the start menu folder, and putting your app or a shortcut to your app into the start menu\Startup folder ...
  • The much simpler way of the registry. Plus, this way the users won't delete this from starting up.

    Place a new key in one of the following folders :
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

    For looking at how to write to the registry take a look at this page ... Basically, you need a dword key put in there. Doesn't matter what you call it, but set the value equal to the path to your file -

    i.e. My_New_Key as the name, "C:\Path\File.exe" as the value.