Help with making a background process in Windows

Hi all,

I want to make a program/dll that'll run as a background process in Windows. I want to a process that can be called when another program tells it to. So lets say that I have a program called Foo. And when I start up Foo it'll tell the process to come alive, and it'll send some data to it. And, then the process will go back to "sleep" or inactive. And then, when you close Foo, it'll tell the process to wake up again and it'll send it some more information.

I'm not even 100% sure that this can be done in Windows. Is there something like this?? And if so does it have a name??? And can anyone gimme some basic help on how to start something like this???

thanks all.

-Phil