Else,
You're over complicating this with too much Star Trek mentality... time is just an abstract idea assigned to the passage of events, nothing more.
I think you have over simplified time. Perhaps you have not heard of Eintein? Time is deffinately not just an abstract idea, it is real and it can be manipulated (slowed, stopped,). You should not make such dogmatic statements with scant understanding of the subject.
Physicist still do not yet comprehend exactly what time is, Einstien started to give us a better picture of what it is, but far from complete. Quantum theory does shed a little more light on it but we are still in the dark. And the String theory promises to perhaps enlighten us even more about the "nature" of time.
On,
Also, "time" as such is rather like Coriolis and centrifugal forces: a fictitious perceptual anomaly of the Riemannian tensor manifold that best describes the geometric nature of our universe, as best we can determine for now.
This can be a very complicated subject, that is very speculative in nature. I think the phrase "best we can determine for now" to be very appropriate. As I mentioned that some have proposed the idea of time running backwards in the "big crunch" which I think Stephen Hawkins seems to favor, I may be wrong but I think he does or did at one time.
The whole concept of time reversal is highly speculative, since we don't yet understand deeply what time really is or what forces cause it.
My interest is though if time is running backwards how would we know? Of coarse this is a specultion. But if it was I don't think we would know.