PC Tools' Spyware Doctor 3.8 offers solid protection against adware, spyware, and rootkits in an easy-to-use and feature-rich interface. The company releases frequent product upgrades, which come with the $30 annual subscription fee. As a result, we performance-tested version 3.8 of the product and then user-tested version 4.0.

In tests performed by AV-Test.org, Spyware Doctor ranked second overall among the five antispyware products tested for the "Spyware Specialists" story. Version 3.8 detected 90 percent of adware and spyware samples and disinfected 50 percent of adware-infected files and Registry entries (a first-place ranking).

As with all antispyware products, its adware disinfection results are partly a reflection of policy decisions on what is adware and what isn't. For example, PC Tools no longer classifies as adware the free version of HotBar, an ad-supported Internet Explorer toolbar, and won't disinfect it, as our tests confirmed. On the flip side, PC Tools has reclassified WebSearch as adware; although Spyware Doctor 3.8 didn't detect it, the company says version 4.0 will. Spyware Doctor disinfected 65 percent of spyware-infected files and Registry entries (a first-place ranking shared with the beta version of Webroot Spy Sweeper 5.0) and was the only tested product to detect 100 percent of active rootkits.

Spyware Doctor 4.0 was easy to install and use. I liked its scan results interface, which cleanly categorizes possible infections with brightly colored bars and detailed levels of threat classification. But the results themselves were a bit alarmist. In my informal user tests on a PC, Spyware Doctor counted 287 "infections" (going with its doctor theme) but categorized the vast majority as low-level advertising and tracking cookies. While it took only a few seconds to realize that most infections weren't dangerous, the growing triple digit count during the scan did quicken my pulse. Spyware Doctor also identified as present a high-risk keylogger and an IM worm that three other antispyware programs did not. While I removed those files without consequence, I couldn't be certain whether they were false positives or real threats that the other programs could not detect. I asked PC Tools to comment on these particular files, but didn't receive a response in time for publication.

Spyware Doctor offers some useful additional features. It lets you set a system restore point, in case of accidental deletion of important files; it protects against your visiting known phishing sites (sites that fraudulently solicit financial and personal data); and it supports scanning of instant-messaging clients. Currently, PC Tools supports MSN Messenger and Live Messenger but plans to add support soon for AIM, Skype (file and text transfers only), Trillian, and Yahoo.

-- Narasu Rebbapragada