Virus problems?

Some advice please.
I seem to have been under assault by the Netsky P @mm virus over the last three days. About 30 episodes of e-mail detections all with the same message.

E-mails labelled "unable to deliver your message" scared me. NAV deleted the worm and quarantined it, but then found the worm in another file and had to delete.

In a bit of a panic I ran NAV and AVG free and the Netsky remove tool from Symantec: no virus found.
Searched the REgistry for the known entries: Nil

Am I infected?.

Also, have had an e-mail with the Sober virus detected already!