These popup windows are called "splash panels". You can't turn them off globally. Some software products (Symantec's for instance) include an option to turn them off, or you can find a RegEdit fix on the company's tech support site. Otherwise, you'll just have to live with it.
Splash panels have two purposes, from the software developer's point of view. One, when a program takes a little while to load up and display its first window, a splash panel informs the user that his request for the program was executed. Some impatient users have been known to double-click the program icon again on the theory that their mouse moved or something. Second, splash panels usually have a copyright notice, which establishes a legal theory for the company if they should have to prosecute someone for making an illegal copy. Since you had to have seen the copyright notice (yeah, sure!), you can't claim you didn't know it was copyrighted. Rick Sprague