There is a new e-mail worm which can affect Microsoft Outlook and Outlook Express users, as well as ICQ and IRC. The subject of the e-mail will be "Hi" and the body of the message talks about a screensaver. This worm will only run if you open the attached file, it cannot autoexecute. One of the things it does if it runs is try and delete your antivirus files so that your antivirus program can't work.
To get more information, go here:
http://vil.mcafee.com/dispVirus.asp?virus_k=99272&