Why do you keep using it? Which are the benefits? Why don't you use an emulator and retire it?
[1]: http://www.geek.com/tech/a-commodore-64-has-helped-run-an-auto-shop-for-25-years-1672510/
[2]: http://www.rollingstone.com/movies/videos/george-r-r-martin-tells-conan-his-secret-weapon-a-dos-computer-20140514