I contacted Pinnacle about this and they said it was a known error on Windows 7 x64bit and that they're working on a fix, but don't have any ETA on when it will be released for public consumption. So, I suppose, it's problem solved until they do manage to perfect it and optimize the programming for x64bit.
All I have to do in the meantime to avoid this catastrophic melt-down is to NEVER tick "Enable OSD" and also not touch ANYTHING in relation to aspect ratios or the size of the window, asides from maximizing/minimizing. Then it doesn't happen and everything's cool.
VideoSpin, on the other hand, is a whole new beast on it's own. One little misplaced process (i.e. dragging ONE too many scenes in the Edit portion) and it completely melts down. But other than that, it works for what I need and so long as I walk on egg-shells with it, it will continue working for what I need.
Just need to shell out the $15 for the advanced codec packs and it'll be great.
Again, thank you all so very much for your help! Greatly appreciated, as always.