PROS: 1) Astonsofts program PC DoorGuard 4 (PDG-4) HAS been able to catch some Trojans/Bots that other scanners miss. 2) Definitions are regularly updated. CONS: 1) The Support is NOT there, Period. Their mailbox, full. 2) It freezes when scanning the file SNDSrvc.exe which is a critical Norton 2006 Anti-Virus file. 3) It stops updating PRIOR to paid subscription expiration. DETAILED REVIEW: I originally purchased it for $29.99 and installed. After one year, it stated that the subscription/definitions were one year old & out of date, so I paid an additional $19.95 for another years subscription. Approx 5 months later, when I went to update the definitions, it popped up a $10 nag. When I clicked the "ok" to this "Nag", it now will no longer allow updates of definitions. I have sent MANY MANY emails over a period of several months to support and other email addresses listed at their site about these problems. They simply do NOT respond at all... Please Go To download.com to read other customer reviews of Asonsoft's PDG-4.