Help me install/play the game!

I was an Elemental pre-order and I played the game for a few dozen hours, back when it was still pretty messy. I decided about a year ago to get back into it, and that's when my problems started. I tried updating Stardock (after the GameStop takeover) and the process stalled, and I haven't been able to play the game since then. Here's what I'm seeing:

Stardock won't launch *or* successfully uninstall. I've even tried Revo Uninstaller.

I can't install the new GameStop client because old Stardock won't uninstall (or work, either).

The old version of the game won't launch on its own; it opens the launcher window, but neither the "Update" nor "Play" button actually functions.

I can't install a new (now standalone) copy of the game anywhere else; when I download the current (1.40) version from the Stardock website and click on the installer, it gets to about 21% on the "Extracting" bar and simply quits (with no error message). (If I "Run as admin" on the 1.40 installer, same thing - it quits at 21%.)

At this point, I'm pretty frustrated that I paid full price for this game as a pre-order customer and haven't gotten to play it since it got more stable/polished. Any suggestions?

(And fyi, my system is otherwise totally stable. I've played dozens of other games - standalone and via Steam and Origin - since this problem started last year. I seriously doubt this is due to system-wide issues. And it's the same system that successfully played Elemental for quite awhile in the past, in the game's first 6 months or so. Win7 64-bit, 8GB RAM, Radeon 5870.)

Also, while I'm at it, how do I change the email address associated with my Stardock account? I've looked all over and can't find the option.

Thanks!