>my system is stay on Novell 4.2 Lan Server.
>all office user have right to access the prg/data directory.
>but....i find that, they can open my database file in his ways (run local VFP to open OR open dbf file from EXCEL).
>
>how to protect my database file ??
You can't. You can only make it harder. I wouldn't think it as a big deal. If users want to harm their own data then it's up to them.
If you want to make it harder, use DBC level rules for fields and tables. Use triggers. ie: A simple trigger might be :

lCanUpdate = (type("oApp") = "O" and !isnull(oApp) and oApp.AppName = "myApp")
return lCanUpdate

Yes users might delete trigger or modify it I know. But whatever you do would be unpenetrable depending on how good hackers they are.
You could also use audit trailing too. But IMHO it would only make it complex on your part not theirs.
Cetin