Novarg was just discovered yesterday.

I received an email yesterday with the text "The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment." It was an obvious virus ploy, but I was curious because Norton didn't catch it. The attachment was a Zip, which I opened carefully, to find a .SCR (screen saver) file. I then went to Symantec's Web site, and found an alert on the front page about Novarg. The description matched what I got, and what you got too. I don't know about MyDoom, the description matches Novarg.

Symantec has removal instructions here if you need them. I don't think you do.

The first message you received is probably unrelated. Sounds like some worm somewhere impersonated your email address when it tried to mail itself to the pfizer account. I don't think it came from your computer, and your computer is probably uninfected.