I can make this happen in .951 on the opening menu:
1. Start up the program.
2. When the opening menu appears, switch out of the program using Alt+Tab.
3. At some later point (after possibly switching back and forth between other programs and this program multiple times, running other programs, etc.), press the "New" button. The button sound goes off, but the screen doesn't change, and appears to be locked up at that point.
It probably does this in .950 as well,
Every other game that I have does this switch correctly, so I don't think that this is a hardware or driver problem.
It would be nice if someone from Stardock can reply to this thread so we know that they have seen this bug report. This bug effectively stops you from using the computer for anything else while playing the game (or at least makes it really annoying).