Please Help Regarding Following Topics,

1:- In my project, when I am opening a login screen, I dont want to
give access to any other form. As in windows XP, when we open Help-
>About Windows Screen , we cant acess any other options behind the
About Windows Screen. Or in VB we write code like Form1.model.
I want above things to happen in Java. Can some one tell me how to do
that.

2:- When u open any application, e.g. VB. And if u tires to open it
again, then it will prompt the screen, "Application Already Open", how
to do such thing in Java ?