The Melissa virus was the big story of 1999. Named after a lap dancer, Melissa was the first major emailing virus. Upon infection, it used Microsoft Outlook to send copies of itself to the first fifty names in the address book. March, 1999, saw it spread across the Internet, clogging up email servers everywhere it went.

1999 was a busy year, with the ExploreZip virus appearing in Jerusalem in June. This one had a fake Zip file attached called "Zipped_Files.EXE." If the user double-clicked the file, it would put up a fake window saying "sorry, this zip file is corrupt." It would then go on to email everyone in the address book, and follow that by destroying documents and files on the hard drive.

The LoveLetter, or "I Love You," virus hit in May of 2000. It was another emailing virus, this time using VBScript. The user would receive an email with an attachment usually called "love-letter-for-you.txt.vbs". Notice the dual extension at the end. Many Windows systems will not display the extension, so the ".vbs" would disappear. The user, thinking he's looking at a .TXT file, feels free to open it, and thereby infects his system. The LoveLetter virus is widely known as the most expensive virus attack in history, with expert estimates upwards of ten billion dollars worth of damage.

2001 was the banner year for viruses. Sadmind in May, Sircam and Code Red in July, Code Red II in August, Nimda in September, and Klez in October. Sircam randomly selected files from an infected machine and sent them out in emails. Nimda attacked through five different methods, including security holes opened by Sadmind and Code Red II.

Through all of these virus attacks, many computer experts pointed to Microsoft as the problem--because most of these viruses were attacking security flaws in Microsoft programs, especially Internet Explorer and Outlook.