This really depends on your definition of the word star. If we take NASA's definition of a star; "a sphere of gas held together by its own gravity", then none of the stars that we look at in our night sky are actually cold, and they couldn't be. They're made up of hydrogen and helium, and even the smallest stars in the sky have a 1000°c or higher temperature. So no, what most of us know a star to be couldn't be cold. However, we do have "brown dwarfs" in the universe, which can be referred to as stars, but they're really not large enough to be defined as a star.