help!

2nd blaster attack on my computer

help! i was infected with the blaster worm when it first came out -- then d/led a patch -- everything has been okay since then until today when a norton anti-virus message popped up and said my comp is infected with the worm. do i d/l the patch again -- so far i am online and have not seen any complications.

edit: i have d/led another patch, but when i scan for viruses again -- it says: delete failed. what do i do???