I have a customer that is running a program called T-Quoter - basically it is a front end program based on an Access database and interfaces to QuickBooks. They used to have Windows XP systems but we added a new one running Vista but after working extensively with their support, they came up and said it would not work with Vista so we upgraded it to Windows 7 Home Premium and it worked for the last 8 months. They just purchased new Windows 7 Professional boxes and we put the programs on these with new serial #'s - every one has worked except for this original system. We open the program; it asks for the serial# and you click Activate - it says you are activated and to restart - once you do this, it just comes back to serial# screen again. When we talk to their support, they say to deactivate UAC (done); turn off all firewalls (done); remove Antivirus (done) but other than that, they are telling us to re-install Windows 7 - we dont have the full version of this for one, because it was an upgrade and the other is that it did work on this system for 6+ months and nothing has been changed - other than the program. They say it is not allowing the program to write to the registry. Is there anything that would be in Windows 7 Home Premium that would not allow this? Since this is a fully loaded system, I am looking for any other answers. Thanks.