Some highly rated free programs that prevent spyware and viruses as of 2015 include Ad-Aware Free Antivirus Plus, Malwarebytes Anti-Malware and AVG AntiVirus Free 2015. Although all three programs are free, they feature premium versions that include features such as heuristic protection and password encryption.
Unlike Malwarebytes Anti-Malware, the other two programs provide real-time protection against spyware, while all three are capable of detecting and removing threats such as worms, Trojans, rootkits and spyware. Windows 7 comes bundled with Windows Defender, a free utility that protects against spyware and other malicious software. Users can access Windows Defender through the Action Center in the Control Panel and use it to scan the computer for spyware infection without impacting the computer performance severely.