Been chasing this around since it was useful to me in WoW.
Since Demonbuddy(others may) does not have a scheduler and some of us believe it safer to only bot so many hours a day, I find it easiest to shut off my bot 4-5 hours before I wake up. This of course is due to the fact I cannot always be at my computer to start/stop due to work/life/etc and would like optimum botting time. The method I use requires Notepad, Command Prompt, and Task Scheduler which are all already on your windows system.
1. Run "cmd".
2. Type tasklist and find the 4 digit ID of your Diablo III.exe. (We'll say 1234 as example)
3. Open a new notepad and type: taskkill /F /PID 1234
4. Save this file to your liking but end it in ".bat" (killD3.bat for example)
5. Run Windows Task Scheduler and set a time to run your newly created .bat file.
I am a 1/10 when it comes to any type of programming so this is as simple as I can get. Originally you could do this without finding the PID (process ID), but for some reason windows cannot comprehend the space in "Diablo III.exe" and I can't see to find how to fix that. Of course, if anyone else has a way around that please share.
Safe Botting!