HijackThis is a free utility that analyzes a user's computer for potentially harmful malware and hijackware. It scans and generates a log file of all running processes, registry keys, and other areas that may be targeted by malware. The software allows users to identify and remove any suspicious or malicious files or settings, helping to protect their computer from potential security threats. The latest version, 2.0.3 Beta, includes updates to support newer versions of Windows and improved detection capabilities.