I have had Creative Suite 2 Premium running on Vista Ultimate for more than 2 years. Photoshop now loads but will not run. It gives the error message 'Your Adobe Photoshop user name, organization, or serial number is missing or invalid. The application cannot continue and must now exit'.
Check out this Adobe fact sheet and see if you find any satisfaction.
Many thanks Curt Y. I uninstalled 4 elements of CS2 and then reinstalled. Everything is working again.