on your last question - go to control panel and click the security button yourself to double check- then you will know it is the real thing if it says the same info as the pop up said.

I set my updates to just tell me when there are new ones and then I read what they are before I decide to download them by checking the box or not.
But most don't have any problems with the updates so you should be fine with them turned on.

If you are sure all your Verizon protection is running then you can turn off the XP firewall.