Well I tried to install Cubase LE4 yesterday. I worked on it for 4 hours, going round and round the "KEY is already in use. I uninstalled and reinstalled 3 times and then gave up.
I sent a support request to them but nothing yet.
I searched and found that hundreds of people had this problem but no answers. i'll wait and see what the Cubase people tell me if they ever do. All the advice I found on their boards and others were to do what I'd already done. What a bad activation process. It's like having a new car and no keys.

Wayne, (waiting for a reply from Steinberg)