there is a network administrators version, once you have found it on their updates site, yo can save it to disk, and use that to update xp to sp2 offline, also its handy to get save sp1 to your pc and burn that to disk, then you wont need to be connected to the net next time you install xp.

i'd recommend you scan for viruses and make sure you have xp's firewall enabled or use somebody elses like zone alarm, kerio etc.

or my top tip would be to use a hardware router with an inbuilt firewall