This is just in the off chance someone has the question and wants to know the experience at some point.
What is the Microsoft Virtual PC?
Apparently it goes back a ways, but currently it is packaged in the 'Professional' and above versions (in my case Windows7). Effectively it lets you run a virtual 'PC' inside your PC, protected from your normal operating environment. So for example you can install an older Win95, 98, XP and so forth and run software in those environments without worrying about later changes in Windows7. There are also other commercial choices as well; this one happens to be convenient, and free as well. But you may wish to explore all the choices.
Why Use It With Libronix3?
If you like Libronix3, it is beginning to have problems with IE9 (needing a patch to alter registry values) in Windows7-32bit and more significant problems in Windows7-64bit (problems with resize, etc). Running Libronix3 in a virtual box protects it from changes to IE and also works on a 64bit system as well.
The other issue I wanted to solve was to be able to use my library in the off-chance Logos.Inc disappeared for whatever reason. That meant making sure of the license ownership/possession, and the software as well. And using a virtual PC on a 64bit environment means probably at least 10-15 years operability into the future.
What Are the Pluses/Minuses to Libronix3 in MS Virtual PC?
When you download VirtualPC from Microsoft and install it, it's pretty much a no-brainer. No special settings, etc. It automatically installs XP which includes the older IE. Applications (like Libronix) are installed from inside the box (running it first), but after applications are installed, they can be run from the regular W7 desktop and appear as if they're just one of many 64bit applications. So, you can alt-tab between all applications running, copy between each, read the USB drive or CD/DVD drive, etc.
Important as well, the VirtualPC automatically expands its disk memory as you copy more into it. So for example, when installed, it might only have 500mg, but as you copy your Libronix library in, it automatically expands to the gigs you need.
Visually and operationally, I haven't seen any difference between my Libronix3 running on XP, Windows7-32 and the Virtual PC. There IS one exception, however. The Microsoft Virtual PC uses 16bit video. Their argument is that it allows integrating the application seamlessly with the other non-virtual applications. The impact is primarily on Libronix highlight-pens in colors. Those Libronix colors on the text are 32bit and so appear as greyish blobs on the text. Not so good! But other forms of highlighting are ok ... colored underlines, colored text, etc. Everything else appears to work normally. I installed other speed-hogs in the VirtualPC as well, and they're actually faster than my Windows7-32 environment (database retrieval, etc).
Installing Libronix3 on MS Virtual PC
The easy way is to go to the Logos site from within the VirtualPC, and run the two files that Logos has for Libronix3 (a main file plus an updater file. Both put Libronix3g in the VirtualPC. Then either on the present PC or another one you have Libronix3 running, backup your licenses, and then copy the license file, plus your resource directory onto a USB-memory. If you also want your settings, etc, they're located in 'My Documents' which can similarly be copied over.
Alternatively, VirtualPC can also install from an older Libronix CD/DVD as well (may have an older version though).
Then from within the VirtualPC, copy from the USB into the equivalent location in the VirtualPC (Program Files for resources, 'My Documents' for settings, etc). Re-start Libronix3 and restore your licenses from your USB and restart again. It should pick up your library, settings, etc. If not, check in Tools > Options > Resource Paths and make sure the path is inside your Virtual PC, not the PC's regular diskdrive (it's possible for Libronix3 to reach outside the box for its paths). Same goes for your 'My Documents', as for the resources.
That's it. The highlighter pens are a negative, but I switched to underlining in colors. And I can now operate Libronix3 right beside Logos4 on my 64bit Windows7. See both at the same time with no issues. Copy across as needed. Use the strengths of both, as needed. And plan into the future.