Why not use the free one at http://adblockplus.org/en/
From what I can tell, this "Pro" is riding on the reputation of another good software.
I downloaded through CNET downloads two copies of Adblock Pro 64-bit software. In neither case did I ever receive a user key. I paid my $19.95 in each case and they gladly took my money. But in neither case did I get anything else via email. And after 14 days of "trial period" the software expired and now I get annoying messages every time I boot up that I have zero (0) days left on my trial.
I've written to AdBlock Pro three times, and each time has received no response. I did get an emailk from Digital River showing that they had downloaded the software (which I already knew) but even on that notice there was NO KEY.
These guys are a joke. I'm hoping that somebody from CNET or this forum can help me resolve this issue.