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.
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.
Virtual Hard Disk or VHD acts like a normal hard drive built into your computer. Cool thing is, it comes in a form of a single file so you can make a copy of it and virtually attach it to any other Windows computer.
