Can you get into safe mode and try system restore?
You could try Stinger click here which can be downloaded onto a floppy disc in another machine if you can't get on to the download site with the infected pc.There is also a MyTob removal tool by Symantec [email protected]" title="http://securityresponse.symantec.com/avcenter/venc/data/[email protected]" TARGET="_new">click here which is also small enough to fit on a floppy disc.
click here for PC Advisors news report on MyTob worm.
While on this sort of problem I wonder if it is worth looking at how (and if) Norton is updating itself on this system?
From reading past threads and reviews I get the impression that Live Update seems to get its definitions updated once a week. The manual job, from my memory of the sales pitch, seems to update "every couple of days or more often if necessary"
In this day and age I am aware that my free Avast seems to update every day, and sometimes 3 or even 4 times a day. F-Secure, which I used to run until it fell out with Zone Alarm, prided itself on updating fast and again often had more than one update per day
I don't really want to get into the Norton for and against argument but I just wonder how effective the (auto?) updating is on this computer