Lets us say you have just download a new album or game
but all the files are .xxx and you need them to be
zip's, rar's, mp3's etc.....
then do the following

-create a new folder
-put all the files needing editing in the new folder
-then goto "run" in the start menu
-type in CMD and click ok

-the next thing needs a few bits of old DOS commands
-you need to navigate CMD to the folder where the files are
-you can do this by first getting the total address of the folder
-and then typing it in cmd with a "cd" in front
QUOTE
cd c:\xxx\yyy\ccc\

once you in the folder where the files are you can move on..
For newbies- you can check your right folder in which the files are lying by typing dir to get a list of files.

-now type in....
QUOTE
rename *.* *.zip

Nb change the zip to what ever the extention needs to be (.rar, .mp3 etc)

all done
you should have now changed the .* to what ever you needed

happy downloading!!!

To exit CMD type in "exit"