1) Are you in the same time zone?
2) In which direction (forward or backward) is the error?
3) Where does (or do) the discrepancy show up? (file time stamps, transaction-unique time stamps, etc.)
4) Is the time discrepancy tied to any particular application that you can identify?
5) Are there ANY apps (legitimate or otherwise) on her workstation that could account for this? Use autoruns (from Sysinternals – Now part of Microsoft Technet) to account for all of them – and eliminate them one at a time until you find the culprit.
Write back and let us know. The more info we have, the better. And… you may well answer your own question in the process of gathering information.