File formats - understanding the different file types
Any file on your computer must be associated with a program for it to work and every program you use will have a specific file format. Whenever you save a file and give it a name an extension is added after the file name which tells Windows what type of file it is.
When you double click that file to open it Windows will read the file extension and open the appropriate program. A Microsoft Word file would look like this "filename.docx" as you can see the .docx is the file extension that Word uses and comes after the file name.
Windows will hide the file extension from you so that you can't mistype or change it because doing so will prevent Windows from opening it. Windows uses icons so you can visually see what type of file it is. You can of course right click a file and have a look at its properties, this will show you the file extension.
The icons above represent the different file types associated with Microsoft Office. Every program on your computer will have its own icon for its files. Taking the time to learn the different file types will help heaps and will give you more confidence using a computer.
Media Files
Your photos, videos and music are classed as your media files. There are many different formats for media files but unlike Microsoft Office for instance most media files can be opened by various programs. For example, Windows Media Player (WMP) can play most video and audio formats and the Windows image viewer can view any image format.
WMP cannot play all video formats though so for this reason I highly recommend using VLC Media Player. VLC can play any video format you throw at it and it's the only program I use for watching movies. There's a link on this page under the free software section.
Associating a file with a chosen program
At some point you may wish to use a different program for certain types of files. If I decided to play all my movie files with VLC instead of WMP I could either;
A) Use the file menu in VLC and navigate to the file from there.
B) I could change a setting on the media file so when that type of file is double clicked, it always opens with VLC Player.
Option B is the best choice because when we want to play a video file or view an image we tend to double click the file to open it, we do it this way because it's easier and faster than option A.
In the example picture above i have some audio files in my music folder. As you can see the filename extension .wma tells me that the file type is a Windows Media Audio File, hovering the mouse over the file brings up a box which confirms that. Any file with the .wma extension will be opened with Windows Media Player. The icon displayed on the file (highlighted by the red circle) is the WMP icon.
To change the default program for any file is simple, there are a few methods but the best option is to right click on the file you want to edit then navigate to "open with" and select "choose default program". There you will see a list of programs that are compatible with that particular file and you just choose the desired one. Once you have done that you will see the file has changed its icon to represent the program it will open with.
As you can see above once we selected VLC Media Player as our default program, the icon changes to the VLC cone icon.
If you would like to learn more about file extensions go into your control panel and open default programs. Choose the second option (Associate a file type or protocol with a specific program) and there you can see many file types and the programs that use them. This is a great way to learn the file extensions and customize the way you want to open your files.