Anti-malware software is designed to detect, prevent and remove malicious software -- known as malware -- from your computer. Microsoft Windows Defender is included in Windows 8.1 to protect you from security threats. In addition, commercial security applications specialize in anti-malware, including Malwarebytes Anti-Malware, Spybot and Kaspersky. Most anti-malware software automatically removes malware it detects on your system, although it may prompt you to confirm the removal. It's important to keep your anti-malware software updated to identify new security threats.
Microsoft includes its own security tool in Windows -- Windows Defender -- to find and remove potentially malicious software, viruses and spyware. When Windows Defender identifies harmful software, it attempts to remove it from your system automatically. While Windows Defender automatically scans your computer on a regular basis with real-time protection, you can manually scan your system whenever you want. Go to the Start screen, open the Charm bar and click "Search." Type "defender" and then select "Windows Defender" from the search results. Select "Full" under Scan Options and then click the "Scan Now" button to scan your hard drive for malicious software.
Malwarebytes Anti-Malware security software detects and removes malware. The premium version of Malwarebytes Anti-Malware is available for a yearly subscription fee of $25, and it provides you with real-time protection and automatic scans. You can download and install the free version of Malwarebytes Anti-Malware or a 14-day trial of Premium from the Malwarebytes website. After you install the software, select "Scan" from the top toolbar, "Threat Scan" and then click the "Scan Now" button.
Spybot is one of the Internet's original anti-malware security applications developed for Microsoft Windows operating systems. Spybot scans your computer for hidden malware and trackers and removes them from your system. While Spybot's Free Edition doesn't support real-time protection, anti-virus protection or automatic scans, you can purchase a one-year license of the Home Edition for $14. After you install the Spybot Free Edition, click "System Scan" in Spybot's Start Center and then "Start a Scan" to start a full-system scan. Click "Fix Selected" to repair or remove any detected threats.
Kaspersky Labs has developed several different tools to protect your PC from security threats. Kaspersky's Free Security Scan is a tool you can use to scan your computer and identify malicious software; however, you cannot fix any threats discovered with the free version. If the free scan identifies a threat on your PC, consider Kaspersky PURE 3.0 Total Security, which is available for $90 for one year of protection on up to three PCs. The suite is available for a free 30-day trial.