What are they?
Why should I change them?
2016 update: the windows may look different but the principle still
some background: All files (almost) in your computer are identified
by a file extension. Most of you will recognize (.doc) and (.jpg)
as files you create with a program. Click
Here for a discussion of file types and links to identify various
other page explains that Windows knows what program to open because
it associates every file extension with an action, usually opening
a specific program. For example, if you have a file that ends in .DOC
and you double click the file, Windows will start Microsoft Word and
open the file in Word. If you don't have Word, Windows will open WordPad.
This is pretty straightforward since .doc is only associated with
one of these 2 Microsoft programs. Many other extensions are associated
with only one program. For example, .PDF is always associated with
files are not meant to be opened. Examples are .exe, .dll, .vxd. These
are all Windows program files that you are not interested in looking
at or opening.
files can be opened by any program in a category. The best example
is the graphic category which includes .BMP, .JPG, .TIF, .GIF, .PNG
& .PCX to name a few. There are many graphics formats beyond this,
but these are the common ones.
here is where the problem comes in. You try to open one of these files
and it opens in the wrong program. It may have been changed when you
installed a new program or for a variety of other reasons. First of
all, lets find out what program is associated with an extension. I'll
use .JPG since it is the most common.
My Computer and click the Tools menu. Then select Folder Options from
the menu. Then select the File Types Tab and the flashlight will look
for the existing registered files types. Then a list will appear.
Then you scroll down until you find .jpg as shown in the next 3 figures.
in my example, the .jpg is associated with Microsoft Photo Editor.
the windows shown here are typical of Win Me and XP. In older
versions, the file types are not listed in the alphabetical
order you see here. They are listed in the Details area, so
you have to highlight a selection to see the extension. Once
you highlight one, you can use the down arrow key on your keyboard
to scroll down the list.
the association is not what you want, it is very easy to change it.
I used to use the "Change" button, but I always had problems
after that with error messages saying the file could not be found.
A much more accurate way is to just Delete the association using the
delete button at the bottom of the window. Then the next time you
try to open a file of that type, it will bring up the Open With What?
Window and you choose a different program and Windows recreates the