The service pack, undoubtedly the last for the aged operating system, was released to Windows Update as an optional upgrade, and stand alone executables were added to Microsoft's download servers. To paraphrase -- and, at the same time, contradict -- Winston Churchill, although this isn't the end of Windows XP, it's certainly the beginning of the end. But we come not to bury XP, but to praise it -- and to answer a few last-minute questions now that it's really, truly, yes-indeed available to anyone who wants it.

Can I really get Windows XP SP3 now? Yes. You can grab it from Windows Update (WU) or download a stand alone installer from Microsoft's Web site.

Will Windows Update automatically download and install XP SP3? Not yet. Instead, you must choose "Windows Update" from the Start Menu, then click on either "Express" or "Custom." In both cases, WU will offer XP SP3. In fact, it will offer SP3 before any other update or patch.

To start the 30-minute process, click the "Install Updates" button.

Microsoft has said it will flip the switch for automatic download and install sometime this summer.

Where's the stand alone installer? As is its policy, Microsoft has also posted a much larger installation file that doesn't require WU. The XP SP3 stand alone installer, which weighs in a 316MB, can be at http://www.microsoft.com/downloads/details.aspx?FamilyID=5b33b5a8-5e76-401f-be08-1e1555d4f3d4&DisplayLang=en

Anything I should know before starting the update? You could just jump into the fray, but Microsoft has a whole list of steps it recommends prior to installing XP SP3. The list found at http://support.microsoft.com/kb/950717/� talks about prerequisites and hard disk requirements, mentions (but doesn't recommend) disabling anti-virus protection and suggests several other moves, including making a full backup before you begin.

That document is also a good resource, or at least a good starting point, for troubleshooting a balky XP SP3 update; it includes information on a host of potential error messages.

You also need to uninstall any now-obsolete release candidate or beta of SP3 that you've stuck on the system.

Anything else? Yes. Microsoft has warned users of Internet Explorer 7 (IE7) that they won't be able to easily revert to the older IE6 once they've upgraded to XP SP3. And in other browser news, the company's also told users who have installed IE8 Beta 1 that they should not install SP3 due to �instability problems�.

Microsoft recommends that users who want to retain the ability to downgrade from IE7 to IE6 should uninstall the former before upgrading to XP SP3. Once Windows XP has been updated to SP3, users can then install IE7 and if necessary, later restore IE6. IE8 Beta 1 users should also uninstall the preview before upgrading, Microsoft says.

Why did Microsoft delay rolling out XP SP3 for a week or so? The company said it had only recently discovered a compatibility bug in the retail point-of-sale software it sells to businesses that cropped up in XP SP3 (and also the newest version of Windows Vista , SP1). As a result, it postponed the expected April 29 release date in order to gain time to fix the problem.

What's new in XP SP3? As we've said before, not much. It does include a few new features, however, which are of more relevance to business rather than home users. The biggest change, at least in terms of the number of users it will impact, is the modification to product activation. New installations of Windows XP SP3 will give use