Microsoft bought GeCAD RAV in 2003 with the intent of using that antivirus engine in Windows.
It's also worth pointing out that the 1998 antitrust case against Microsoft is most known as a Browser fight, but it included a heavy hand from Adobe and all of the major Anti-Virus tools of the time. It was seen by many at the time, including Microsoft, that the delivered court decision forbade Microsoft from including PDF software, anti-virus tools, firewalls, and other such software in Windows (and arguably against building some of them at all).
It's somewhat easy to understand why that decision almost made sense in 1998, but real easy to see why it aged very quickly like spoiled milk (including the wide spread of spyware and malware that soon followed).
It's also worth pointing out that the 1998 antitrust case against Microsoft is most known as a Browser fight, but it included a heavy hand from Adobe and all of the major Anti-Virus tools of the time. It was seen by many at the time, including Microsoft, that the delivered court decision forbade Microsoft from including PDF software, anti-virus tools, firewalls, and other such software in Windows (and arguably against building some of them at all).
It's somewhat easy to understand why that decision almost made sense in 1998, but real easy to see why it aged very quickly like spoiled milk (including the wide spread of spyware and malware that soon followed).