How was it installed, via migration from backup or older computer or via original installer?
Have all updates been installed which are available for CS6?
It was re-installed using the original disc, the remove preferences box was ticked as well.
I asked you: Which OS?
Have all available updates been applied?
No updates as installed from disc
I asked you several times:
Not only Windows! Which version? If this answer is not given, any response is only guessing, as e.g. Windows 10 is not fully compatible to CS6.