You can rely on Z-Cron as a robust scheduler that can handle not only shutting down the computer, but also launching programs, leave reminder notes, and cleaning directories. Similar to the Unix Cron scheduler, and far more powerful than the native Windows task scheduler, Z-Cron is an aggressive sergeant at arms, able to tell your computer what to do and when to do it, leaving you to get on with your life when you're away from your machine. Besides tasks, Z-Cron also has the capability to schedule tasks to run daily, weekly, monthly, once, and regularly at your system start-up.
The most useful tool that Z-Cron possesses, and what makes it such an excellent utility, is that it comes with a database of Embedded Tools. These tools are the basis for everything it can do, and they include a range of tasks such as an alarm clock, the capability to shut down a remote computer on your network, activate a USB peripheral, and connect or disconnect from the Internet.
Note that the installation is in German, although the program is in English. Still, that's not a cause for concern: getting the program going is about as simple as can be. The value of being able to have the computer do necessary tasks while you sleep or while you're away is a great weapon in any power users' arsenal.