Q:I recently used Windows Update to upgrade my computer. Now it seems to be very slow. Did I do something wrong?

A:Probably not. But Microsoft did. Windows Update is a feature built into Windows that allows users to upgrade their operating systems with a couple of clicks, thereby introducing new operating system features and fixing flaws. The industry calls this "installing patches." Microsoft has introduced a number of patches over the past few years, many of which enhance the security of Windows whenever Microsoft developers plug holes that could be infiltrated by hackers. Most of these patches are good; but a recent patch, #811493 "Security Update (Windows XP)," caused tremendous slowdown problems for users of various anti-virus software packages. The patch should not have been released. Yet, since many users get the updates automatically using Windows Update, unsuspecting users were slowing down their systems. Microsoft has since taken down the patch, and is revising it for rerelease.

In the meantime, if you suspect that you have installed the patch, you should remove it from your system. I'm putting instructions in my next Megabyte Minute Tip Letter (being delivered this afternoon), which you can get for free at www.MegabyteMinute.com

SARS worm wreaks havoc

If you receive an unsolicited message with information about SARS, don't open the attachment. It might infect you. Not with SARS; with a worm called Coronex. According to security company Sophos, the Coronex worm will change settings on your computer, copy itself into files that will run every time you restart Windows, and send a copy of itself to people in your address book. While it might be able to distribute itself widely whenever somebody opens its attachment, the Coronex worm does not do a lot of damage. At least not now.

It also changes the start page of Internet Explorer. So a more damaging effect can be delivered to you when you open up Internet Explorer to surf the World Wide Web.

The worm is carried to you in e-mail messages which typically have subject lines such as "Severe Acute Respiratory Syndrome," "I need your help," "Virus Alert!", or "SARS virus," depending on the day of the week it is sent to you. (I'm not kidding. Apparently, it uses a different name on Monday than it does on Friday.) It also copies itself onto your system in the guise of files that you might confuse with games you play or movies you've seen.

Among the files that contain the Coronex worm: Doom 3.exe, The Sims: Unleashed.exe, The Lord of The Rings.exe and Jedi Knight II.exe.

Symantec's virus definition was updated on April 23 to include the Coronex worm.

A fix for the worm also is included in Sophos Antivirus release 3.70, also known as the June 2003 release. McAfee added it in virus definition file (also known as DAT file) #4259.

As always, make sure that your virus definitions are kept up to date, whether you use one of these or some other anti-virus software.

If you manually update your virus definitions, open your anti-virus software now and make sure that your definitions are no older than those I've just mentioned.

Better yet, have your anti-virus software update them automatically -- preferably at least weekly.