Lev,
I don't have an answer for you but want you to know you are not alone. PD7 is one of the buggiest pieces of software I've ever used. Pinnacle Studio was once the "king of video editors that crash a lot" but PD7 can now claim the title.
The most challenging thing I do is to edit in AVCHD on a 2 year old computer. PD7 handles it but works feverishly to do so. I waste lots of time waiting for PD7 to constantly scan huge files before it will allow me to advance to the next step.
I also recently purchased Sony Vegas Movie Studio Platinum. I'm amazed at how well it handles anything I throw at it without breathing hard. It is extremely quick and never crashes. The down side is that it is far more complicated than PD7 and has no ability to create BluRay menus. For that you must buy their $500 package but even then you'll spend LOTS of time doing the simplest of tasks because everything is from scratch.
I've used many editors in the past and recently converted from Pinnacle Studio to PD7 based on glowing reviews and a feature set that goes beyond the competition when you consider that the other packages constantly are teasing you with supplementary products to enhance the creative process. It is easy to spend over $500 on Pinnacle Studio when you add all the "optional" products and content they offer.
Pinnacle proved that they could make a more stable product though they have a long way to go to be as stable as Sony Vegas Movie Studio. I'm hoping that someday CyberLink will be at least as stable as Pinnacle Studio as PD7's feature set and design is better than most.
So, today I use two products - CyberLink's PD7 and Sony Vegas Movie Studio. I use SVMS to capture, trim, render, and create reverse motion video and PD7 for editing, effects, corrections, and disc authoring.
This was my "work around". I hope you find yours.