Usually, you should backup the Windwsupdates/security patches BEFORE formatting;
and then apply them BEFORE first connection to the internet, or update behind a properly configured firewall (evem activation of XP’s built-in firewall should be enough for this…)
Otherwise, you’ll be hit/infected by a network worm in next to no time again…

As to formatting…
it wears the harddisk, but not too much, I’d guess…; BUT:

  • you should configure your PC securely, so that you don’t GET any viruses/malware anymore…
  • when you always format, you don’t know through which security hole the virus/malware entered your PC, and it’ll probably happen soon again…

→ see above board search, too :wink: