Kaspersky Anti-Virus 2015 offers full spectrum security for your Windows machine. In addition to their free PC antivirus offering, there are several premium versions available, and we're trying their entry-level product. Kaspersky Anti-Virus 2015 runs fine on Windows 8.1. It leverages data sourced from the larger community of Kaspersky users to identify the newest threats. You'll also enjoy real-time virus protection, a rollback function that undoes the nasty work done by malware, and a web browsing monitor.