Since many of the heavy metals are superconductors at extremely low temperatures and life is based on movement of electric charges, currents, is it possible to have life based on these superconductor atoms at a really low temperature?
Doubtful, for one basic reason. The temps at which natural superconductors function is extremely low - usually a few degrees above absolute zero. At these temps most chemical reactions will not occur. Since the formation of life requires the building of metabolic networks, which are nothing more then sequences of chemical reactions, its hard to conceive of a living system that could undergo any form of metabolism (and thus self-organization) at such low temps.
This may seem trivial, but keep in mind that in your hypothesis you do need at a minimum a source of free electrons - where are those going to come from aside from some sort of chemical or photochemical system? Likewise, you are going to need energy to organize the superconducting "tracks"; they won't self-organize without at least a modicum of external energy to mediate the re-organization of the system. Finally, for a biological system to do work (in the physical sense) you need to consume energy - superconductors are great at transporting electrons without expending their energy, but by their very definition do not consume that energy. Ergo, to get movement or biochemical reactions out of those superconducted electrons, you're going to need some non-superconucting chemistry. Its doubtful anything would work at the kinds of temps you're talking about.
But cold (although not superconducting cold) temps are an interesting idea to ponder. At extreme cold many chemicals behave in ways quite different from what we normally see - water, for example, can form numerous unique "ices" that are chemically very different from the ice we normally see. Water is far from unique in this case. Who knows what kind of biochemical bounty may exist at these cold temps? Life of this sort would be slow - chemical reactions proceed painfully slowly at these temps - but it could take on forms beyond our wildest imagination.
Bryan