The House of Commons, Microsoft, Intel, the Federal Reserve Board, the Department of Defense, Silicon Graphics and Cox Communications are but some of the thousands of institutions that have been inundated with email containing the self-replicating "I Love You" virus, which later in the day resurfaced under another name: "Very Funny."
Beyond corporate damage, consumers may also have been affected by the virus, which overwrites music and graphics files. As a result, MP3 music collections and personal photo albums stored in digital formats may have been damaged or lost.
The Web site for security expert Symantec slowed to a crawl because of heavy demand for virus inoculations.
The worm hit Washington hard, forcing the State Department, the Army, the Internal Revenue Service and the Federal Emergency Management Agency to close email connections to the outside world, Reuters reported.
By and large, companies acted swiftly to prevent the virus from being activated by warning employees, shutting down mail servers, and running antivirus software on PCs. These actions likely helped to slow the spread of the virus, which can destroy images and other files on hard drives.
Still, containment has meant long hours and extra work for IT departments. Analysts estimate the cost of battling the virus could total several million dollars, with much of the expense coming from downtime, antivirus scans and other curative measures.
Winbond Electronics, a Taiwanese memory manufacturer, shut down its email servers worldwide after first noticing the virus and then contacted all of its IT employees to get to work to contain the problem.
"The MIS department came in at 2 a.m.," said a spokeswoman at the company's Silicon Valley offices. Antivirus programs were run on each desk, and bulletins were plastered all over the office instructing employees not to open email containing the virus.
"We went into crisis mode," the spokeswoman said.
Because of experiences with previous viruses, such as Melissa, many other companies also closed their email systems to prevent problems. Xerox shut down its email servers, according to sources, as did several public relations firms. One PR firm volunteered to send information about security breaches from a client, but the firm's email system was down.
Many emerged relatively unscathed, though. Charles Schwab spokeswoman Rebecca Metz said the virus hit the company around 4 a.m. but created only a minor stir.
"The only thing we really noticed was an intermittent slowdown in email delivery earlier in the day," she said. "It hasn't really impacted our business or our ability to reach our customers."
Diana Gapuz, a spokeswoman for Pacific Gas & Electric, said, "It was basically a nuisance, but it didn't disrupt our regular operations in terms of delivering energy." She added that the IT department kept the company informed through voice mail.
Although it was compared to Melissa, today's virus is far more potent, security analysts said. Like Melissa, the self-replicating virus generated a deluge of junk email, flooding corporate servers. The virus also destroyed files.
Those hit hard by "I Love You" could take a lesson from stodgy accounting firms. Workers at only one of the "Big Five" firms said they use Microsoft Outlook, with Lotus Notes the client of choice among other number crunchers.
The lone holdout, KPMG, was hit hard by both Melissa and by "I Love You." Spokesman George Ledwith said the firm took down its email network early this morning. As of 4:00 p.m. PT, the company was still working to get it back up.
"We're taking prudent actions to bring it back up," Ledwith said.
The crippling of corporate email systems has meant brisk business for some firms that provide Web-based alternatives to intranet-based email systems.
"We're very busy," said Shane Jones, CEO of eProject.com, which offers file sharing, calendars and other tools for an online "collaborative workspace."
"People rely on email, so we've had an increase in sign-ups," Jones said. "Normally we get several hundred new users per day. Today we've seen a 40 to 50 percent increase."
For others, the day had a personal touch. Richard Weaver, who works for a Web start-up on the East Coast, noticed an "I Love You" email from a close girlfriend early in the morning when he came into work. "I thought she was trying to tell me something, but it wasn't what I wanted to hear in the end," he said.
"Nothing appeared after I clicked on it, so I knew then that it was a virus," he said. The virus spread quickly to other computers in his company, but Weaver already had warned them, so no one opened the attachment.
News.com's Michael Kanellos, Joe Wilcox, Evan Hansen, Paul Festa, Ian Fried, Sam Ames and Troy Wolverton contributed to this report. Reuters also contributed.