Vista SP1 breaks networking

After SP1 downloaded as an automatic update, Vista Bus. Ed. became highly
unstable and repeatedly dropped the LAN connection to the ADSL router, and
only a reboot would bring it back.

My support call to Microsoft got a really very unhelpful response, saying
that I should do a hardware compatibility check before installing the
update. They have to be joking. The fact that it was an automatic update
escaped them entirely. I don't think they even read my email - I suspect it
was automatically generated from keywords.

After hours of messing around trying all sorts of different things,
resetting my router, changing the network card, etc, I finally found that if
I turned off automatic acquisition of the TCP/IP address for the network
adapter, and hard-coded that and the DNS address, the system was back to
normal.

My question is why on earth did the update do that? How many PCs are now
crippled because people don't have the expertise to fix the problem?

Andrew
(I'm glad I got that off my chest.)