In VFP7 there is standard sys() function for this
SYS(2340) - NT Service Support
See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fox7help/html/lnlrfsys2340-ntservicesupport.asp

>While doing some critical log entries, I dont want the users to kill the application by "End Task" from Task Manager. With "ON SHUTDOWN", the maximum I can do is put up some dialog and inform the user not to kill the application. But still the users can go ahead and kill the task.
>Is there some API, which will work across all the platforms, and prevent the user from killing the application?

HTH