Photoshop v8 installation onto Windows 7 invalid personalization issue

I have a CS Premium Suite and have recently installed it onto my Windows 7 notebook. Unfortunately, when I open Photoshop it comes up with the error:

'Could not complete your request because of missing or invalid personalization informationi'. All other applications in the suite load ok with the serial number displayed on the splash screen. It was a clean install. I note that the serial number is not displayed on the Photoshop splash screen when it starts up.

I did some testing and grabbed a 'fake' serial number to install photoshop 8 directly from the cd rather than via the suite install and it loads fine. However, I couldn't keep it as the serial number was illegal and therefore, wouldn't activate. The point is, the software will work fine on my Windows 7.

Does anyone know how to fix this?

Thanks