PC101-Personal Computer 101

How can I figure out what this file is and does?

All files on your computer are identified by their 2->4 letter file suffix (or "extension").   For example an executable program file would normally have ".exe" as a suffix identifying it to the computer as an executable program, e.g. "Word.exe".

To see the file names and extensions (suffix's) you can use the file manager program called Explore.  To open this program right click on Start and then select Explore.   The file and folder names are on the right side of this utility window.   You will not be able to see the file name extensions if you have that option turned off.   To check, select the Tools tab in Explore  and then Folder Options...    Select the View tab and then go down the list until you find Hide extensions for known file types.   Make sure the box next to it is NOT checked then click OK.

Here is a short list of common file suffixes and what applications they are related to.   For more rare or exotic ones see the links at the bottom of this article.

File Suffix/Extension                 Application/Program                        Notes             

.EXE	Executable Program
.DLL	System Library file
.TXT	ASCI Text	MS word processing
.DOC	MS Word file	MS word processing
.WPS	MS Works file	MS word processing
.RTF	Rich Text Format	MS word processing
.HTML, .HTM	Internet webpage file
.BAT	MS-DOS Batch	A program file in DOS
.DB	OS database file	e.g. "thumbs" image list
.TMP	temporary file	file needed temporarily
.LOG	logging information	logs program results
.PDF	Adobe Reader	generic internet info
.JPG	graphics	photograph or image
.GIF	graphics	photograph or image
.DIR	folder	not usually visible

Of course there are very many more extensions on your computer system, so you will need to research any not listed above.   The layered applications (programs) on your computer often create their own unique extensions, so knowing this may someday allow you to find the correct "home" (program) for an orphaned file.

Finally, you can change the suffix of a file if you desire and you can also tell the system which programs to run for a specific suffix, but this is much more technically advanced than this website is designed to get into.

Links to finding out what a suffix is:

File Extension Source website

Or you can use the MS link below:  copy this link into your browser URL window and replace the ??? with the suffix you want information on, e.g.:

http://shell.windows.com/fileassoc/0409/xml/redir.asp?Ext=txt

http://shell.windows.com/fileassoc/0409/xml/redir.asp?Ext=???

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