Loss of Internet Coonection sharing option

Any help gratefully recieved.

I have two laptops. A wireless connection with excellent strength. They used
to communicate, file share, print, connect to internet. One acting as Host
the other Client.

Both systems run XP

When I set up a new wireless connection and subsequent Home/Office network
everything stopped working.

I can create a wireless connection, with excellent strength, but under '
Wireless Network Connection Properties', 'Advanced' tab there used to be two
options - Windows Firewall and Internet Connection sharing - now there is
only Windows firewall. ICS It is not simply greyed out, just not there at all.

any ideas? I assume that this is the reason that when View Entire Network is
selected, each machine can only see itself.

regards