The second patch blocks three security holes in all currently supported versions of Windows: Vista (including Service Pack 1), XP SP2 and SP3, and Windows 2000 SP4, and 64-bit versions of Windows.

The , which let Web developers write Web applications. As a user, you may not interact with these services, but they're on your PC anyway. One bug (rated Critical by Microsoft) affects only XML Core Services 3.0. The other two (both of them rated Important) affect later versions.

Be sure to apply this patch pronto. If you have automatic updates enabled, the patches should arrive automatically. But patches want to install themselves at once, usually followed by a reboot. Rather than tolerate the interruption during a busy day, I have my system set so I can pick when I want to do the updates. If you're like me, or for some reason didn't get the automatic download, get the patch from .

Patches for Firefox

As , white- and black-hat hackers are poking around more intently in search of security holes. In fact, Firefox 3 has had two different patch releases in the past two months. The latest, version 3.0.4, fixes four sets of newly discovered bugs that the browser's volunteer developers rank as critical.