If you have deployed SP2 to your SharePoint Farm then you should definitely read this. There is known bug that converts your farm into Trial Environment for 180 days.
Luckily, there is easy solution, in a sense that you need to retype Product ID in Central Administration:
What happened?
http://blogs.msdn.com/sharepoint/archive/2009/05/21/attention-important-information-on-service-pack-2.aspx
How to solve it?
http://support.microsoft.com/kb/971620
Read the complete post at http://www.mcpblog.net/Lists/Posts/ViewPost.aspx?ID=56