I want to know some command prompt tricks?

I have a little cousin who likes to be on the computer too long. I'd like to know how to make an administrative account, shutdown the computer remotely, give the shutdown a countdown, send him a message, and delete the admin account I made to cover my tracks; all with command prompts and on the Windows 7 operating system. It's a lot to ask but if you could direct to anyone who can tell me or i'll take that too. Thanks.