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.
If you are tired of waiting for your Windows 7 computer to shutdown or restart, you can create a new shortcut that will speed up the process considerably.
Windows 7 have a nifty feature which combines the windows of opened applications under the same taskbar button. If you don't like it you can always turn it off.