How to set Explorer so that you can see file endings
First a bit of history (skip this if you just want to know how to do it)
When PCs were born and the Microsoft Operating Systems came into being, the way the operating system knew how to associate a file was by the "file ending" this was the three characters after the dot at the end of a file name. In DOS (Disk Operating System) based systems like MS-DOS versions 1 to 6 and MS Windows 3.1 and 3.11 which were basically an application (called Windows) running on top of DOS, the operating system limited file names to what we called an "eight dot three" file naming convention. In other words all files had to have a name part that was less than or equal to eight characters, followed by a full stop or "Dot" and file extension made up of three characters.
In the early days that would be things like ".txt" for a text file, ".bat" for a batch file (a sequence of DOS commands put together in a script to do some useful work automating a task or whatever). This all changed when Windows 95 came out and suddenly the file length limit increased to 255 characters including drive and folder parts of the path, but again there was a three character file extension after a dot at the end to identify the file type. With the release of Windows 95, Microsoft was copying some of the ideas from MacIntosh operating system one of which was the idea that a user was file oriented rather than application oriented. What this means is that the DOS/Windows brigade were used to starting our applications like Word and Excel and then going to the file menu and selecting "open" this would then open a file dialog where you could navigate to the document you were interested in and select and open it.
Mac users didn't do this, they found their document and double-clicked it and relied on the operating system to know which application to start that could edit it ... poor dears. Unfortunately this sloppy thinking had by Windows 95 crossed over to the Windows PC and Microsoft allowed users to adopt this method of opening and editing files. To be able to do this the operating system when faced with a double-clicked file has to have a way of knowing what type of file this is. In the Mac each file has a lot of baggage associated with it in a thing called a "resource fork" so instead of there just being a single file with three letter ending the Mac maintains a whole bundle of hidden files that co-exist with the actual file you want to open. The system interrogates these additional hidden files to find out a) what type of file that is and b) where the application is that can open it. If you are a PC user and you receive a file from a Mac user and have hidden files tuned on you will see all these additional files copied to your system.
On the Windows PC the system keeps a database of all file extensions and the applications that are associated with them, so if you must double-click a file to open it (rather than doing it the proper way), Windows will read the 3 or more letters after the last dot in the file name and look up that in its internal database and then launch the "associated" program and load the file automatically just like a Mac.
How to show the file endings
By default a clean installation of Windows XP, Vista or Windows 7 will hide the file endings when viewing files in Windows Explorer. Being an old hand with PCs since the days of DOS I like to know the file ending, if it's a Word document it ends in ".Doc" or ".Docx" if you are running the newer version of Microsoft Office. Likewise if it's an Excel spreadsheet it's ".xls" or ".xlsx" if it's the 2007 or 2010 versions of Excel. So how do you turn it on?
First open Windows Explorer (Windows Flag Key + E), then go to the "Tools" menu. In Windows Vista and Windows 7 the "Tools" menu may be hidden from view, to bring it back, press the "ALT" key at the bottom left of your keyboard. On the "Tools" menu select "Folder Options", the following dialog will appear:
As per the above picture, switch to the "View" tab and then scroll down the list of tick boxes until you get to the entry "Hide extensions for known file types" which will be ticked in your version. Untiick that option (meaning "Don't hide extensions for known file types") then click the "OK" button in the bottom of the dialog to make it stick.
NB: Clicking the "X" in the top right corner of this dialog (or indeed any dialog in Windows) will cancel the action, always press OK in dialogs if you want the changes you have made stick.
NB: Some people insist on clicking "apply" then "OK", there is no point using "apply" in this way. Apply is exactly the same as clicking "OK" but it doesn't remove the dialog from the screen. The whole point of the "Apply" button in dialogs is to allow you to make a change and then preview the effect without losing the dialog and having to go through all the steps to get back to the dialog again if you decide you don't like it. If you know that the change you have made is what you want (in this example turning file endings back on), then don't mess about, just press "OK" as you are done with the dialog.
Now you will see the file endings and all will be right with the World.