License after reinstallation on newly installed computer

I had to reinstall my Computer and was not able to deactivate the em-Client. Now on reinstalling I get the message that all licenses (6 are licenced) are in use. How am I able to reactivate the license on this particular PC?

Hi Manfred,
you can login into your account on our licensing server (you need to use Internet explorer for this and have Microsoft SilverLight installed).
You can manage and activate/deactivate your licenses there.
If you do not remember your licensing credentials, message me from the email under which you registered at and I will send reset email with your licensing credentials to your account.