Well...there is a possibility that the CMOS battery ran down at some point.
When that happens, the system clock is reset to the wrong date and time...the user/owner must change it or it will remain incorrect. Then the date stamps on all files moved or changed will be incorrect.
Happened to me (I was unaware that the date had changed in the BIOS)
I'd like to say "not likely" but it can happen.
You can compare the created date of system files and other files. If no system files were created after a given date, that is highly unlikely (due to security updates).
Edited by hamluis, 08 January 2009 - 08:50 PM.