I just checked my e-mail and noticed MA3 Beta11e was out. So I downloaded it and uninstalled the last version from the Windows Uninstaller. I then right clicked on the downloaded file and selected Install. It installed fine and when I checked there was only one installation in the list of available screensavers.
I was able to set up my fish and add some MP3 tracks. I noticed though that every time I exited the screensaver and went back to the screen saver settings panel in Windows 7 that the settings option and test option were unavailable. So closed the the window and then re-opened it again from the Control Panel > Change Screensaver option. Thus I was able to make changes to the MP3 list and load in a photo for the crystal.
When testing the changes, I noticed the fish were starting to judder, there was no MP3 playback and the hard drive was thrashing about, so I quit the screensaver again, and looked at the task manager. I found I had 6 copies running!
http://www.screencast.com/t/OWNkMTI2NzMt
Never had any problems on Windows 7 Home Premium before with the last beta or the installer version which is the one I had running before.