>Hi! is there any one who can tell me in short that whats the major difference between VFP6 & VFP7 is Microsoft provided some login security on database or not ?

You can learn 'What's New in Visual FoxPro' at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fox7help/html/newwhats_new_in_visual_foxpro60.asp.
There's no database security in VFP 7 but you can implement a limited one using new DBC events http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fox7help/html/necondatabasecontainerevents.asp.