In any case, Laserlight already answered the question a while ago:
Actually one of the challenges on this site is to write a quine. There's even a nice solution to it.
Actually quines do have some uses. Some viruses that are built with showing off in mind (core wars) will make copies of themselves by outputting their own source code into a text folder and compiling itself. Well you can kind of call that a use...
I doubt if they still remain quines but for one thing they can make some changes in their source and then compile!
A kind of self evolving virus
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.