Yes without the past we would have no future, we must not dwell in it either, but be mindful and we can learn from it or how to change and improve. We can also see how far we have come and how much has changed over time.

"Why should we look to the past in order to prepare for the future? Because there is nowhere else to look." (James Burke) 

Sure, if you can learn with past mistakes you avoid them in the future

http://www.youtube.com/watch?v=YIQguao8Gfw

Yes without the past we can't live the future,we repet always the same fault and without the faults of past  it there will not be life (what do you think!?)