JS.Loveletter is a worm that reaches computers in an e-mail message that warns about the risks of a previous version of the same virus. It also spreads through the IRC chat channels.
The message contains a file called PROTECT.VBS, which contains the virus code. On running this file, JS.Loveletter deletes all the files with the extensions VBS,VBE, JS, JSE, CSS, WSH, SCT, HTA, COM, BAT, MP3 and MP2 that it finds on the affected computer.
In addition, every time it infects a computer, JS.Loveletter sends out a message containing the virus code to all the contacts in the Address Book.