Windows 98 won’t see the MS06-15 patch
It turns out that Windows 98 is just too hard for Microsoft to support with a security patch for MS06-15 now. The official support period ends in July, but they’ve announced that this one won’t be getting a patch as the changes would be just too substantial. Some of the mitigation suggestions involve using restricted zones settings to limit ActiveX and Active Scripting. (Of course, installing something other than Windows 95/98/ME might be considered a mitigating factor as well.)