Hi Steve, I’ve been looking here and at other forums with folks dealing with problems in upgrading their existing DAW platforms, to make them more powerful and faster.
I thought just purchasing a new i7 2600 4 core based, Windows 7 computer would solve my problems. I’d just install all of my older Steinberg programs in the 32 bit x86 program files area and press on. Not So!! 
I have learned about "Hardware Security Protection"which is on my original install disks such as Steinberg’s “WARP VST” (guitar amps and cabinets) for example. The hardware security protection on the disk will not recognize my new cd/dvd rom drive. 
So I’m kinda’ in the same boat as you and many other people in deciding if I should keep or dump my old expensive DAW system, or replace EVERYTHING. I’m on a tight budget and I don’t expect any hit records to be produced out of my humble abode anytime soon.
So I plan to get the most out the equipment and software that I’ve already invested in over the years. The only reason I bought a new computer a year ago, is because my nine year old Windows XP machine had died of a hard drive or motherboard failure.
I see you have built an older spec’d quad core machine to run all of your VSTI’s off of your main audio machine. I assume you are using System Link to accomplish that? I hope that you can continue to find work-arounds for your existing equipment.
Bill