Same issue--new computer unable to see the activation window. Thank goodness for this thread as it helped me get through it, but I did want to add a step I had to take.
After taking the resolution down to a low setting, I was able to see the activation window, but I could not see anything being typed into the code blank. Even though you can't see it, it should still be there, so go ahead and hit Submit. After hitting submit, it didn't look like anything happened. I changed resolution to a different low setting and it showed the success screen.
