An old problem with Photoshop has re-appeared with CS6. For no apparent reason Photoshop loads multiple help screens which sometimes block all activity. I reported this many years ago but it was never explained. Now after severla changes of computer and operating system it has re-appeared.
I am using Photoshop CS6 under Windows 7 Ultimate on an AMD Phenom Quad core with 8 GB RAM.
In the middle of doing something the online Help screen opens up. If it was only once that would not be a problem, but it opens up maybe 5 or 6 times, and if I try to close one Help screen another opens.
If I can manage to finish the last Photoshop command I can close all the screens, but sometimes I had to use Ctrl-Alt-Del to get the Task Manager to close Photoshop.
I had exactly the same problem with earlier versions of Photoshop but it seemed to have gone with CS5.