That might've helped with maybe 30% of the issues, even behind firewalls and w/o UAC you also had all the early IE fault (Let's make ActiveX run x86 code from u

That might've helped with maybe 30% of the issues, even behind firewalls and w/o UAC you also had all the early IE fault (Let's make ActiveX run x86 code from untrusted sources... facepalm) that let adversaries get an initial foothold on computers. Regular Windows usage back around y2k was just insecure, compared to then MS has really made strides.