Hello from Hull Erik!
To get you started, look up the "at" function. It will allow you to schedule a file to run at a certain time.
I can't test it here because I'm at work and they have disabled it (I would need Admin privileges) - security reasons I assume.
Out of curiosity, what are you trying to accomplish? Is it just so users will have it open when they get to work, and it will shut down later in case they forgot? I'm just always interested in the uses for Access that people can come up with!
Later,
-Sean