It defends your computer against malware attacks with multiple layers of protection using proactive, reactive and automatic protection to stop threats at every entry point. Integrated Behavior Guard blocks new threats faster than traditional security software, and Browser Defender™ protects against web-based attacks – including phishing attempts, scare tactics and malicious automatic downloads. This version of Spyware Doctor also lacks the antivirus engine that its bigger sibling Spyware Doctor with AntiVirus provides, and as such, it’s more comparable to Ad-Aware than a complete antivirus and antispyware program like Norton. The program comes with some useful settings options, too, including a gaming mode and the option to run a scan at start-up. However, its default setting for rootkit scanning is off. While the trial version of Spyware Doctor can’t remove detected threats, it does offer real-time protection–much like PC Tools’ free ThreatFire program.
PC Tools Spyware Doctor with Antivirus 2010 protects your computer by a multi-layer approach:

Site Guard (Layer 1): Websites known to be sources of malware are blocked
Browser Guard (Layer 2): All scripts are analyzed in real-time and stopped if containing drive-by-downloads and similar threads and nuisances