I had to re-install Act!2009 on my Vist Business PC.
Since then, nearly each time I open Act! it requires an Activation.
Please see if the solution offered in the following Knowledgebase article resolves the issue:
You are Prompted to Register ACT! After You Have Already Registered the Program
Greig HollisterNote: Effective 6/1/13, Sage no longers provides support for the Act! software. This is now provided by Swiftpage.