I've moved your post to the General folder. I thought about putting into the Firewall topic, but I can't say that the problem is with the firewall. I suspect that the issue is a general Windows issue with the patch.
I just encountered what you are describing on my laptop. It took the patch last week when it was released, but last night it took 2 more Vista updates along with my other 2 Vista machines. Today, I found that I was unable to connect to a valid Share on the laptop via the network. I turned off the OneCare firewall and I was still unable to access the Share. All remote connections were blocked, too. I decided to reboot once again and all was well after the reboot. Note that I rebooted to complete the installation of the Windows updates. When I rebooted, I was on my home LAN and access to the Shares was fine. The laptop then went to Sleep mode for the trip to the office. I encountered the problem when plugged into the LAN at work. I could see the PC from multiple other workstations, but all attempts to connect to the Share were blocked until I rebooted.
If a reboot does not resolve it, you can contact OneCare support and/or seek help from the Windows Update angle -
Windows Update Solution Center - http://support.microsoft.com/ph/6527
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve
