By default Windows calculator doesn't support order of operation, to enable the functionality you need to activate the scientific view, let me show you how.
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.
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.
If you are using removable disk or USB key then you should look at this lesson. I will show you how you can safely remove your device from computer without the fear of losing data.
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.