I know you can get your program to start when windows loads by putting it in the startup folder, this will then run the program when windows starts, the only problem with this is that the user can hold the left shift down when windows is loading to stop startup programs from running.

I know of a registry key that runs programs separate from the startup folder and this is;

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

I am not sure if you could add your program in here, but you could try.

Hope this helps

Simon.