compiling into a .exe, reminder pop-up, and single user problem..

Question

hi all.. 1. how do i compile my visual basic .net project into an executable .exe file?.. 2. if i wanted to create a simple reminder software.. what are the command codes to cause the reminder to pop up based on the date and time?.. 3. how to allow only one user at a time to access my visual basic .net software?.. will appreciate the help.. thanks all.. :)