There I was, merrily fixing someone's computer. Among other things, they'd been having trouble connecting to Microsoft's Windows Update Web site. The Web site would seem to load up just fine, but when told to check for updates, it would get stuck in an endless loop of checking.

After much hassling, wrangling and repairing, the update process finally resolved, and up popped the list of recommended, important and critical updates. "Oh, no," I groaned, as I saw what was at the top of the list. I could not have been more intimidated had it been Arnold Schwarzenegger's "Terminator" character, grimly staring me down, pointing a shotgun in my face and declaring, "I'm back." Yes, my heart fell as I saw the first item in the update list: Windows XP Service Pack 3 (SP3).

If you don't understand why I have some trepidation regarding XP SP3, read my April 13 article "Windows Vista Service Pack 1 infects, wrecks computers." Maybe I'm being paranoid, or maybe I have too much experience with Windows service packs to feel comfortable about the situation.

XP SP3 was supposed to have been released in 2006. That release date was pushed back to 2007. Finally, on April 29, 2008, SP3 was unleashed, only to be immediately pulled after a "compatibility issue" was found between it and another Microsoft program called Dynamics RMS, a retail business management package. It seems that, after installing SP3, business database files could disappear. The conflict is so bad that Microsoft is telling RMS users to avoid SP3 until the problem is fixed, which they say will be in about a month. Even so, SP3 became available this week to the general public.

What I find especially bizarre is the list of things that Microsoft says you should do before installing XP SP3. The list can be found at support.microsoft.com/kb/950717, and includes:

Uninstalling certain previously released updates.

Setting aside over 1,000 megabytes of hard drive space for the installation.

Temporarily disabling your antivirus software, which, Microsoft advises, may leave your computer "more vulnerable to attack by malicious users or by malicious software."

Logging in as administrator and backing up all of your files to an external location and creating and Automated System Recovery (ASR) set.

The list goes on to describe no less than 23 error messages that can appear while attempting to install XP SP3, such as the always helpful, "An Internal error occurred." Only after performing all of the chores on the list will Microsoft even hint that an SP3 installation might be successful.

Still, many people are reporting successful installations of SP3, with some folks saying that it makes their computers run faster. That's good news.

Conversely, stories abound about SP3 causing many computers to become completely useless. This sort of hit-and-miss update scenario is typical, business-as-usual standard operating procedure for Microsoft.

XP SP3 is, for now, an optional update. However, Microsoft says that, beginning sometime "in early summer," XP users that have Automatic Updates enabled (which is almost everyone) will find SP3 being installed without being given any choice in the matter. My advice is to start backing up your files, prepare your system as per Microsoft's instructions, disconnect from the Internet and disable your firewall/antivirus/antispyware programs. Shut down any other programs that may be running in the background. Then, install SP3 from the full-version download, instead of using the Automatic Updates method. That way, you'll at least be aware of what's going on, instead of being greeted sometime "in early summer" by a mysterious blue screen and a crashed computer.

Dave Moore has been repairing computers in Norman since 1984, when he borrowed $1,200 to buy a Commodore 64 system. He can be reached at 919-9901 or www.davemoorecomputers.com.