How can I configure the machine to reboot at a certain time?

A. There is a command line utility shipped with the resource kit called SHUTDOWN.EXE that can be used to reboot the local machine

shutdown /l /r /y /c

Where /l tells it to shutdown the local machine, /r to reboot, /c to close all programs and /y to avoid having to say yes to questions. You can then combine this with the AT command (don't forget you need the Schedule service to be running (Start - Settings - Control Panel - Services) to use the AT command) to make this happen at a certain time:

AT shutdown /l /r /y /c, e.g.
AT 20:00 shutdown /l /r /y /c

Additions to the at command could be /every:M,T,W,Th,F so it happens every day, e.g. AT 20:00 /every:M,T,W,Th,F shutdown /l /r /y /c

You will then be given 20 seconds before the machine is shutdown, to abort the shutdown type

shutdown /l /a /y

You may also consider ShutdownPlus (http://www.wmsoftware.com/shutdownplus) which replaces the standard Windows shutdown and logoff dialog boxes. Shutdownplus allows you to run applications and stop services (stopping services only under NT/2000) at shutdown, restart, or logoff.