Some installations or settings changes require you to restart your computer. In most cases you don't need to actually reboot it, you only need to restart the explorer.exe process.
In this day of age, it's very practical to have a Windows 7 installation on your USB key, for many netbooks and devices don't come with CD/DVD drives anymore.
If the DVDs, USB sticks, phones, cameras or any other media and devices are automatically starting to play or open explorer windows and your don't want them to, this is how you tweak the AutoPlay settings.
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.
Windows Explorer does not have menu displayed by default like you were used to in previous versions. To activate and keep it permanently visible follow this tutorial.