I upgraded to power dvd 12 recently, but it turns out that powerdvd 12 has implemented cinavia, so i am curious if I get an older version with a valid activation code off of ebay whether I can have two versions on my computer simultaneously? I still need pdvd 12 for 3d, but would use the older version for the occassional cinavia encoded disks.
I seem to recall that once upon a time I used to have two different versions of PDVD installed on my HTPC. When you install the 2nd version, just make sure it's not trying to use the same destination folder as the version that's currently installed. IIRC, PDVD names the folder with the version number so they tend to be unique.
I have PowerDVD 9 and PowerDVD 11 on my computer. Both are in the Program Files directory in the Cyberlink subdirectory under a PowerDVD9 subdirectory and PowerDVD11 subdirectory. Media Browser sees both and I can use either.