How to know if a PC was turned OFF while programs were open

I am trying to determine if users are turning OFF their computer with my database application open. I’m getting some file corruption.

The EXE for the app and the data files reside on the server. It’s not a database such as SQL Server, it’s a Visual FoxPro application.

The computers are XP PRO workstations on a Windows 2003 Server LAN.

Thanks,
Bill