The PC in question is a Dell c521. Maybe this is another nForce problem?
Anyway, build 15031 installed fine, but my wifi stick (Netgear WNA1100, current driver) failed, reporting a possible driver error. I could see the router and enter a password, but could not establish a connection.
Connecting via Ethernet failed too.
I could access properties for both kinds of connection, but could not change them; the cursor would simply spin forever. The usual remedies like ipconfig had no effect.
Speaking of spinning forever, shutting down or restarting invariably hung up on the green screen. Power switch still worked, though.
I've reverted for now, but I can update again if anyone has suggestions.