>Hello,
>
>Please I want to add a command button (Logoff) that when click, will logoff the user and display login window for another user to login.
>
>Thank you

You can do something like this:
In Click Event of the button:
1. Close All opened forms in application
2. Clear all variables that depends of user
3. Reinitialise your appliction as first time runned (This may be includes previous 2 :o)
Then put the Login form in DO WHILE loop and check if the new user login) Something like:

pbLoginUser = .f.
DO WHILE NOT pbLoginUser
   DO FORM MyLoginForm
ENDDO

In MyLoginForm put pbLoginUser = .t. WHEN the user login corectly.

Something like that