From the information I got on this one forwarded here this comes in as a usual type of spam with the invitation seen on the subject line. Often an infected machine will be spreading it through the email contacts stored there.
One way to insure no contacts of yours are infected in the event your machine falls into this is to keep all contacts in writting and clear the address book in Outlook or Outlook Express to prevent the spread. Hopefully you simple press the delete button to get rid of it if you see it come in.
The usual antivirus programs will not prevent an infection from this or other similar variations that appear as attachments on incoming mail. This new goes right after the hidden information stored like the master boot record, partition information, and anything protected there by Windows. AVG and other email scanners may or may not flag an email with this attached. This is why a strong warning has to be put on this one. Usually when a program flags a bug infested email you can simply delete it right away to avoid infection. If you click on it to see what it is "say goodbye" to all data on your drive!