Users of Norton AntiVirus 4.0 and later versions have reported a slew of problems with the product, including annoying computer freeze-ups. With these system hangs, pressing Ctrl-Alt-Delete produces the error message "Msgsrv32.exe (Not responding)." ScanDisk may then create numerous temporary subdirectories (named DIR00000, DIR00001, and so on) that you can't easily remove.

Another AntiVirus-related problem may afflict your PC if you use Netscape Messenger as your e-mail program. The Messenger Inbox may take a long time to open, or it may not open at all. Messenger may stop responding when you try to open a message, and again your system may create many temporary files. Symantec confirms that the virus definitions dated June 16, 2000, and June 19, 2000, are responsible for these problems.

You should get rid of the mischievous virus definitions immediately. To update your virus definitions, choose LiveUpdate from within your version of AntiVirus or point your browser to Symantec's Virus Definitions page. To eradicate the temporary subdirectories created by ScanDisk, however, you'll need to run a specially designed utility from Symantec.

Surf Easy With More IE Patches

Hardly a month goes by without a Microsoft security scare of some sort. True to form, the company recently released the latest in a succession of security fixes. The most serious ones address various Internet Explorer weaknesses that could expose your computer to disaster.

Bug: Simply visiting a Web site run by a malicious operator could unleash debilitating code on your PC, reformatting your hard drive or deleting files. An ill-intentioned site operator could introduce the nasty code via shortcuts embedded in an HTML Help (*.chm) file. That file could reside either on your hard drive (if you were enticed into downloading the file, for instance) or--more likely--in a type of shared folder known as a UNC (Universal Naming Convention) on a remote system.

Fix: The solution prevents shortcuts from being invoked in an HTML Help file unless the file resides on the user's local hard drive. To keep such files off your system, Microsoft suggests, refrain from downloading .chm files from Web sites you don't know. Download the 733KB patch for Internet Explorer 4.x or 5.x running on Windows 9x or NT 4.0 from FileWorld. Windows 2000 users can get a 503KB patch for IE 5.01 here.

Bug: When you whisk off your credit card number as part of a secure transaction with a site, your browser is supposed to verify that the site is the one you think it is. However, two flaws in the way IE 4.01 and 5.01 validate Secure Socket Layer certificates could allow a rogue Web site to pose as a site you trust and conduct seemingly secure sessions with you. The malicious site operator could also read selected files on your computer.

Fix: The first flaw: When you connect to a secure server through either an image or a frame, IE verifies that the server's certificate was issued by a trusted source (like VeriSign), but it doesn't verify the name of the entity or the expiration date. The second gaffe: When you initiate a new SSL session with a server previously validated during an IE session, IE does not revalidate the certificate.

Separate patches for IE 4.01 and 5.01 close the breaches.