Re-entering the key is okay - anyone can live with that, after such major shock as winblows reinstall.
What I did not getting is, the not accepting the key, untill reinstall.
This does happen because I changed the version of the OS, right?
So, next time I reinstall and use SP2 again, it should just accept the key and did not want reinstall FlashFXP again anymore - at least as long, that the OS version remain the same, right?