Blaster worm disabld by removing index

Windows XP with Norton Anti-virus 2002 (fully updated) Blaster repair from MS run and unsuccessful. Helping a family member & running out of time, I was unable to download any MS updates because of certification file corruption so I disabled the BLASTER worm by removing its index files. Worked ok and user was able to access web etc. I have everything repaired now except that the MS download dowsn’t seem to recognize the BLASTER worn and the VIRUS warning pops up continually – Natually repair, quarantine & remove using Norton didn’t work either. I tried to change the Blaster file propeerties – no luck (its read only of course)