BubbleBoy worm BubbleBoy is a script that can be embedded in an e-mail message, and executed merely by previewing or opening the message. This is not an attachment, but rather invisibly embedded in the message itself. It only affects Microsoft Internet Explorer versions 4 and 5, and uses Outlook or Outlook Express. Outside of being a nuisance, BubbleBoy causes no harm to your computer or files. This technique, though, could be used with a harmful payload.
Details are here .
Microsoft has released a patch to prevent this type of attack. This link can be run from its current location or downloaded and run from your hard drive. If you don't open the attachment, you won't be infected. If you double-click the Happy99.exe attachment, you are treated to a beautiful fireworks display while your computer is being infected. I have written a batch file which will disinfect the virus.