I would first advise against doing this as it makes the point of locking the computer a mute one. Additionally, i do not know that the Windows Task Scheduler will allow you to usurp its protection measures.
I do know that in some computer BIOS (if not all BIOS) you can have your computer at least turn on/wake up at a certain time each day. Or there are free software programs that will do that for you.
Hope this helps