The patch for the cursor flaw in Windows is causing woe to some, as it apparently is incompatible with certain hardware configurations. More specifically, it seems that audio and network hardware from Realtek will be disabled upon applying the patch. Realtek NICs are common in entry level machines with onboard network, so this fix may have affected many. Removing the patch is enough to cure the problem, though of course that puts you right back into the spot of being vulnerable to the cursor flaw. For those affected, Microsoft does have a support article up related to it. Unfortunately for many, their "patch for the patch" is for the audio components, not the networking.
Fixing one thing to break another is an inevitable consequence of a rushed patch. Unfortunately, Microsoft didn't have much choice in this one, as the cursor flaw was apparently being exploited enough to warrant an emergency release. Hopefully, by the time patch Tuesday comes around again, they'll have a more well-tested release.