do you have a router? if so, disable any built in "firewall" option if it has one - all that option does is if it noticed something that looks like an attack (such as loads of search results or channel details being flooded in) it turns off all your port forwarding
if not, check to see if sygate is trying to tell you anything about blocking an attack, although i havent heard of that being a problem with sygate
and i'm assuming the XP firewall is off...?
