QI-ANXIN's Antivirus System is designed to detect and eliminate known types of malicious programs and stubborn Trojans, as well as repair destructive viruses. It integrates multiple engines, including a local engine (QOWL), a cloud engine (QCE), and an artificial intelligence engine (QDE), to provide comprehensive virus elimination capabilities. The Antivirus System includes targeted measures for various resilient viruses, allowing it to remove multiple stubborn Trojans effectively. It supports Windows XP SP3 and above, with the anti-infection mode not working on systems below Windows XP SP3.