Well, when you reinstall windows the Security ID (SID) is different even if you use the same CD-Key. I think Stardock marries serial numbers to SID, so this is probably what is causing your issue. Not 100% sure why this would be a problem if your registry was fresh and your directory was completely over-written unless it uses a common files folder to store the check against your SID. Good rule of thumb when reinstalling windows - back up your data, and do a CLEAN (format) install. If you did that, then not 100% sure what would be happening unless Stardock puts your SID on their servers to match to your CD-Key.

Installing to a different folder worked. Maybe the sig.bin deletion would work as well (I uninstalled shortly after posting this report), but I can't see why that isn't something the game could do by itself once it discovers it is invalid for some reason. Or for that matter, why it's matching anything to the machine SID in the first place.

Draknost, I've installed the game on my work laptop as well as my home comp, with no problems, so Stardock does not marry the game to a given machine.

Now I'm anxious to see the results of all the betas .