500 years of memory?

Of course not, we can't remember things now, I don't remember anything before I was ten, unless there was a drug of some sort that would retain information better, then I don't think so.

I don't think so. If something traumatic happened (especially in the early stages of life), then it could possibly screw up memory-making relating to that experience/subject, and even non-related experiences. That, and I don't believe that currently we have the mental capacity to remember that many memories.

I can remember some events in the past (such as surgeries, funerals, and other things), however I generally can't remember all that much that hasn't happened in the past year or so.

Perhaps, as technology advances (as long as we don't die out...), we'll have a sort of machine version of the Pensieve from the Harry Potter books - though I wouldn't hold much hope of it happening in our lifetime, OR at all, really.