With Windows 7 Adobe moved the flash trust file into the users directory structure. The Adobe documentation still states the ability to have a global trust file that operates for all users, however have not been able to make it work as documented. Maintaining this by user would be a nightmare on a shared machine. Does Adobe have a shared environment solution for Windows 7?
This shortened Adobe manual link describes the Global Flash Player Trust directory: http://bit.ly/fRRV9n