I was one of these people that for some reason could not
connect either wireless or ethernet to other computers or
shared printers. Despite every effort including upgrading
OS.
Sometimes we don't see the forest for the trees.
This notebook that would not connect is used in a field
enviroment and must be protected with a firewall. So
Norton was installed. BUT, the config for Norton was told
to disregard 192.168.1.0 to 192.168.1.25. Making a long
story short. Norton was the culprit all along.
If people have firewalls, be it XP internals or 2nd party
stuff like Norton etc... Disable them and see if you've
found your gremilin.
I have had Norton installed on MANY netowrk installs
before and never seen this...