Maybe it is just me but I don't have any sympathy for people (including businesses) that are still running XP. Jeez, update your damn OS folks.
We apologize for the inconvenience. It does appear that there was a hiccup with an update pushed out causing Windows XP machines to lose Internet connectivity. An update was just released that should address the issue, what I will need you to do is: To get XP users Internet connectivity (temporarily), please disable the Web AV component of your protection policy for your managed computers.