Loss of ICS functionality after executing windows update

have xp home edition, version 2002, with SP1. run ICS via
wireless network (D-LINK hardware). Connect to internet
via cablemodem (USB Port), the shared connection.
whenever i execute (actually download OS mods)a windows
critical update, from microsoft, i lose ICS
functionality. only viable fix, identified so far, is to
disable the shared connection and then re-enable the
shared connection and all performance is restored.

Rebooting, whether prompted or not, does not fix things,
only the process described above. Running symantec
corporate antivirus with religous use of updates - no
virus ever detected (hopefully, will stay that way.)

nothing found in any knowledgebase articles on this one -
any ideas?

tnx mark