Hi to everybody! I have a bizzare problem

Time ago I've copied some file from laptop to a micro sd hc (32gb, kingston) trought my Sansa Fuze V1. Than, later, I copied the same file to external HD, and copied them on my new Desktop PC. Both system have Windows 7 Professional.
Now, If I see the dates (Last Edit) of the files on the Desktop pc, they are all back to 1 hour, comparated with the files to the microsd.
So, same file's Last Edit Date on Desktop pc is 16:12:08, 15:12:08 on microsd.
Why? And how can I set them both to the same data? (without re-write ALL files).
I really don't know how to figure out the problem... looks like rockbox with microsd evalutate dates in different mode
