If you can't do any of those things, then essentially you are unable to properly run other programs. How would you be able to edit a cell in excel if this other program is sitting in front of it? how could you see other windows if you can't move or minimize this other one?
The point is, you may as well password your account then use <windows key>-L key combination to lock your desktop. Hopefully you already have a password on your account and you aren't sharing it with other people. That's the easiest way to keep stuff from moving around when you don't want it to.