If you put your computer into hibernation, the next time you turn it on, you'll get all your windows and programs open just the way they were before the shutdown.
If you leave your computer running on a 24/7 basis you might be interested in determining the amount of uptime that has accumulated since the last reboot.
You have more people using one computer and you don't want them to be able to shut it down using a shutdown button on Windows logon screen, this is how you remove it.
If you can't copy files that are bigger than 2 or 4 GB, usually HD movies and such, on to your USB key, it's usually due to the file system the USB key is formatted to.
A less known but very useful feature that works since Windows XP has been released. You can easily rename a bunch of files in a matter of seconds, let me show you how.