Malware targeting Windows systems are malicious pieces of software that can cause a variety of different problems. It can damage system files, steal sensitive data, or even allow an attacker to gain remote access to a system. The most common types of malware targeting Windows are viruses, worms, trojans, ransomware, spyware, and adware. These threats can be spread through malicious emails, downloaded files, or infected websites. It is important to always be aware of these threats and take steps to protect your system.