>>Dear all,
>>What is the best way to know which users is running the program?
>>I have a MyApp.exe that is in MyApp ( a shared folder ) on my server. I have 20 users that i want to know which user run the program and each user must can only run the program once.
>>Thanks
>
>Create a users table that has one record for each user, when a user logs in lock their record, when they log out unlock it. The security system checks for locks in the user table to see which users are logged in. Log in first checks to see if the current user's record is locked, if it is refuse to allow log in. You can also have fields in the users table to track date and time of last login if you like. If you need more details use a child to the user table to track login and logout but use the active lock as the indicator that the user is still in the app.

Yes, i am using from this method for many years. but now i have a loader for main program.
I have MainApp.exe and Main001.exe, Main002.exe, Main003.exe in one share folder. when user run the MainApp.exe, this run Main003.exe ( as bigger Main???.exe in folder ) this is for program upgrading. but now i lose locked users! i dont know why. so i want to find another way if possible.