Installed the software on one pc (W 8.1) without problems. No on installing at the second system needed to login into a Microsoft Account. Since this was a new account it needed a confirmation. The confirmation e-mail arrived on an other system. After I confirmed the account it went on to start the installation on that system (here I do not want to install office 365 yet)
Going back to the system I wanted to install office in the first place doesn't work. It does not accept the product key anymore and point me to buy office 365 again.
How do I make sure that the product keys stay valid and most important how can I make a fresh start to install the package using one of the Product Keys left.