It seems to have restarted again, so...

If you receive spam from this address, I never sent it.

Spammers, Worms and Viruses (much the same thing),
use data mining software to extract email addresses
from websites and infected computers. 
They then spoof the addresses
in the forwarding of spam or viruses.

It is virtually guaranteed that where
the email says it comes from, is not accurate.

Sorry, I get a hell of a lot of it too!

The only thing to do is make sure your
AV and Spyware is up to date.