www.siteadvisor.com will help you check if you're downloading from a safe source. It's also easy to set a program to start automatically with windows, although I don't know if you can set it to hide itself automatically. Do some googling or search windows help. It's easy. I think you just put a shortcut of the program in the STARTUP folder of the start menu itself. Make sense?
find the program you want to start
RIGHT-CLICK on it and choose CREATE SHORTCUT
RIGHT-CLICK on the shortcut itself and choose CUT
Mouse to ALL PROGRAMS
DOUBLE CLICK on STARTUP and the folder will open
RIGHT-CLICK and choose PASTE
You're done. Easy. Just make sure you configure the program to auto-hide itself when you start (if it can do that) otherwise they'll be able to see the program starting. Don't want that!!