Make a form, Modal to the windows

Hi guys
Well in a part of my app I need to prompt my users with a window and don’t let him/her do anything accept giving the window the password I want just like when you’re logging on to the windows or shutdown or log off you can’t interact with the stuff behind the login window as far as the login window is open as if the window is modal to all the system.
Now I want to know how I can make a window, modal to the windows.
The steps would be:
1. Activating the desired window and set forces to it among other opened applications (but how?)
2. Make the window modal or limiting the mouse curser to the form’s borders
Can anybody help please doing these stuffs in vb.net?
Thank you

helloo? could anybody answer?

Did you ever figure out a solution to this problem? I am trying to do the same thing and can find nothing! Let me know,

Thanks. Jim.