The KB951748 fiasco resulted in users being unable to access the internet normally on computers that had any version of Zone Alarm or I believe at least one other brand of firewall softare. It did not apply to all firewall software, only those that had hooked into the windows system in a particular way. It also did not apparently apply to Vista systems. It had nothing to do with Avast AV software.
The initial work around, to un-install KB951748 certainly worked on XP at least although a reboot after the uninstall seemed to be needed. The current situation for Zone Alarm users is that Zone Alarm have released an update for all of their firewall products (7.0.483.000) and that works fine with KB951748, with Avast 4.8.1201 and 4.8.1218, and with Spybot 1.6 (I can only speak for XP-Home SP2 & SP3 and XP-Pro SP3, and the ZA free Basic firewall software)
For your own protection, I would reinstall Avast. If need be download a copy of Avast on another computer, and also a current copy of the VPS file from the avast site, and copy it onto your PC via a usb flash drive or CD.
You may be able to resolve your problem if you can restore to a date prior to the current problem appearing.
