SAN FRANCISCO: Computer security experts are warning of a dangerous new e-mail virus, one able to destroy information even when users don't fully open their messages.

"Bubbleboy," apparently nicknamed after an episode of the TV show Seinfeld, is the first known e-mail virus that doesn't even need to be fully opened to be activated. Just highlighting the e-mail's subject line in Microsoft Outlook Express activates its hidden code.

It also takes every address in a computer's e-mail program and passes the virus along.

Researchers at Network Associates, a Santa Clara computer security company, said "Bubbleboy" could become the framework for the easy delivery of a host of malicious programs.

"This ushers in the next evolution in viruses. It breaks one of the long-standing rules that you have to open an e-mail attachment to become infected," spokesman Sal Viveros said. "That's all changed now."

"Bubbleboy" was e-mailed late Monday to Network Associates and the company put a free software patch capable of blocking the attack on its website the next day.

The company isn't certain who sent the virus, but researchers believed the threat is so serious that they notified the FBI, said Vincent Gullotto, director of the company's virus detection team.

"Bubbleboy" only requires that the e-mail be previewed on the Inbox screen of Microsoft's Outlook Express, a popular e-mail program. As soon as the e-mail is highlighted, without so much as a click of a mouse, it infects the computer.

The virus appears as a black screen with the words "The Bubbleboy incident, pictures and sounds" in white letters.

It affects computers with Windows 98, Windows 2000 and some versions of Windows 95 that also use Microsoft's Internet Explorer 5.0 and Outlook Express web browser and e-mail programs, Gullotto said. It apparently does not affect Netscape's e-mail programs.

Even without Network Associates' software patch, there is an easy fix. Enabling Microsoft's highest-security e-mail filter will keep the virus from entering.

Microsoft spokesman Adam Sohn said last Tuesday night that anyone who downloaded the August upgrade to Internet Explorer 5.0 already is protected from "Bubbleboy."--AP