There are two ways to rename a file extension ‘without’ a stupid program.

Number 1, Folder Options:

Go into your Control Panel,in Control Panel open “Folder Options” and click the view tab and make sure ‘Hide file extensions for know files’ is not selected, then press Ok.

Now go into a folder and notice you can see your files extensions, rename them to whatever you'd like, for instance:

Code:
Dildos.exe to Dildos.Anonymous / Etc,Etc,Etc



Number 2, MS-DOS:

The difference between renaming files in DOS is that you can rename multiple files rather then one at a time, therefore making time gracious. Here I’ll provide you a few examples.

Go to your start menu and open run, then type “cmd” without parenthesis.Now find out which directory has your files and type:

Example

cd C:\Files\


In your case “C:\Files\” may not exist, so type in the directory that your have you files in. If everything goes will dos will look kinda like this:

Code:

C:\Documents and Settings\User>cd C:\Files\


Now, type: dir
and you will be provided with what files are in your folder, including their extensions. In my case:

Code:
C:\Files>dir
Volume in drive C has no dildo.
Volume Serial Number is CXXX-XXXX

Directory of C:\Files

02/01/2005 07:22 PM DIR .
02/01/2005 07:22 PM DIR ..
01/31/2005 06:40 PM 14,336 stf.bmp
01/31/2005 06:40 PM 14,336 stf02.bmp
2 File(s) 28,672 bytes
2 Dir(s) 39,024,766,976 bytes free

C:\Files>


Did you notice how I had two files named stf. Since both of these files have the same extension, *.bmp they can be renamed all together. If there are other files in there with the same extension and you don't want to rename them, move them to another folder and / or directory.

Last but not least,
type:
Code:
C:\Files>ren *.bmp *.rar


And your results are:
Code:

C:\Files>dir
Volume in drive C has no penis.
Volume Serial Number is CXXX-XXXX

Directory of C:\Files

02/01/2005 07:37 PM DIR .
02/01/2005 07:37 PM DIR ..
01/31/2005 06:40 PM 14,336 stf.rar
01/31/2005 06:40 PM 14,336 stf02.rar
2 File(s) 28,672 bytes
2 Dir(s) 39,024,676,864 bytes free

C:\Files>