On Windows, a file has at least three attributes: Created, Modified and Accessed. while Modified and Accessed could be in any order (it may have been modified after you last accessed it), the one invariant you would expect to hold is that Created is older than either of the other two. Here's a file I just saw on my file system:
Created: Wednesday, August 29, 2007, 9:45:20 AM
Modified: Friday, April 06, 2007, 11:34:55 AM
Accessed: Friday, August 31, 2007, 2:33:41 PM
After considerable searching I finally found a Microsoft knowledge base article about this that explains how such a thing might have happened and, even more usefully, an article that explains the true semantics of these names and articulates the issues clearly. This latter article shows just how subtle it is to define precisely what these times mean—and equally, why it is equally important to define these concepts precisely.