Are you talking about Premiere Elements 8? If so,
Premiere Elements 8.0/8.0.1 will run well on Windows 8.1 64 bit.
Have been there and done that.
Add On...same business about shutting off automatic Background Rendering and AutoAnalzyer features.
When you get a chance, please update us on your progress.
And, do not hesitate to ask questions. We are glad for the opportunity to be of assistance.