"Evaluation period has expired."... what? (SSMS problem)

I have problem with SQL Management Studio 2008. I used for few months Evaluation Edition (before I also used beta and CTP). I do upgrade to full edition (using installer with built-in key from MSDNAA) and everything looks good. But two days ago I got information from SQL Management Studio, that "Evaluation period has expired.". I tried reinstalling all things few times, but with no result. All parts install in normal, full mode. Only SSMS install in evaluation mode. What can I do with it?

PS The same installer on another machine, clean installation and SSMS is not in Evaluation Mode. On my computer I can change date back and SSMS is working, but this is really not a solution.

Best regards,
Dawid