Help I’ve been Hit hard by SirCam

Last week my network was hit by the SirCamm worm and I managed to clean
it off the users machines, but one user’s mailbox still generates emails and
sends them out. I have even deleted this user’s mailbox and NT account,
but still get undetermined messages at the mailsweeper gateway.
Additionally, I reformatted that User’s PC to ensure that traces of the virus were dealt with.

Internally, her messages are still going out to the other users.
During the slack period e.g. in the evening, no messages are being generated
from that user, but they appear during the day, which is weird coz the user’s
account does not exist !!!!! I am quite baffled by the whole scenario. Any
ideas?