You don't need two installations of DVDP, just select File > Open Database. In the opened dialog, you can create a new DB by clicking on New Database

Hi,
I find that any easy way is to "Tag" the entries - it's then easy to filter the listings. I use this to make list of DVDs that I have on my hard drive and another list for those only on disc.
In previous versions of profiler I used to make use of the "ordered" and "wish list"

So, just a couple of ways to keep all your collection or even yours and a friends in one database.