Fixed The Problem Already Hurray
I was a little quick on the draw blaming Premire Elements there. After digging into the Event Log and finding the name of a DLL that was causing problems, then Googling that DLL, I found out that it was nVidia's Stereoscopic 3D driver that was causing the problem! I'm not sure I had this on Vista, I hadn't updated my drivers in a while; but my Win7 drivers are the latest and greatest, and they came with this as a silent install. Uninstalled that program, and voila! PE7 works fine again! Hurray!