Have an "excellent" connection, but still can't access the Interne

Okay, so I am desperate to figure out what I did wrong. I am slowly
learning, but really know nothing about setting up a wireless connection.
That is why I called my provider last week and was talked through the
wireless connection/router set-up process, and I was finally connected! I
then went to my flatmate's laptop and did the same configuration and her's
worked, too, both laptops with an "excellent" connection.

However, when I got home from work later that day, my computer showed that
it was still connected (blinking monitor on my toolbar), but I couldn't
access any website with my Internet Explorer or use any program that
connected to the internet (like Yahoo Messenger). My flatmate, however,
still had full use of the internet, and both of our computers still showed an
"excellent" connection. I compared our configurations again, and they were
the same...clearly, since I had not reconfigured anything since that
afternoon.

I tried disconnecting and reconnecting and even restarting my computer, but
the same problem. I also saw my wireless network on the list of networks I
could connect to say "Not Connected" instead of "Automatic" or "Manual" with
a star next to it, but when I highlighted it and clicked CONNECT, it asked
me if I was sure I wanted to disconnect?! So what does "Not Connected" mean
if I was already connected, and if I was already connected, why can't I
access the internet?

I have tried clicking this and that on and off in my wireless network
settings, but to no avail...and for a few days I lost all connection
(blinking monitor on taskbar showed a red x). At times it didn’t even show
my wireless network on the list of networks I could connect to. As of last
Saturday, my flatmate disconnected and restarted her computer and now she
can't get connected again, but my internet connection magically appeared
again a couple of days after that. ??!! HOWEVER, I’m still not able to
access websites on Internet Explorer or use any program that accesses the
internet…not even if I disconnect the wireless and use the cable connection.
So, recap of past few days: one computer shows an excellent connection, but
can’t access the internet, and the other can’t connect because the wireless
network (that the one laptop is connected to) does not appear on it’s list of
available wireless networks.

I don't think it's a location issue, because the router (a Webmaster 3100SV,
by NTT, the national communications company here in Japan) is right next to
my computer and just a few feet away from my flatmate's computer. The router
is intact and plugged into the electric outlet and phone jack. ASDL and PPP
lights are on and not blinking.

Both of the laptop’s current wireless network settings are:
"Use Windows to configure my wireless network settings" and the
top-of-the-list preferred network (my network's) properties are: Open Network
Authentication and Disabled Data encryption...set to "connect when this
network is in range" Advanced settings: access "any available network(
access point preferred)" and checked to automatically connect to
non-preferred networks. And, yes, the wireless network connection is enabled.

Should both computers have the same wireless network settings/properties?

I also know these settings are not for a secured wireless connection. If
anyone can help me: (1) Get the wireless connection working again on both
computers and (2) configure my connection so that it is a secure one, I would
be EVER SO GRATEFUL!
NTT hasn’t been able to assess the problem over the phone and they are
sending someone out to the house next week to help me. I’d like to avoid
that $100+ charge, if possible, so ANY input you have is appreciated.

Thank you!

 

The only thing different from my setup is you have checked
"automatically connect to non-preferred networks".
You might try this procedure:

Power down all devices, modems, routers and PCs. You didn't say if you
have a separate router and cable/dsl modem, this procedure will assume
you have two devices. Wait about 60 seconds, then power up the
cable/dsl modem. Wait about 60 seconds, then power up the router. Wait
about 60 seconds then power up a PC.

Now try to connect to the network/Internet. This procedure usually
gets everything back in sync.

If your network is the one at the top of the list and it shows as
connected but you are still not getting Internet access, try
disconnecting and reconnecting. Never mind what the messages say, ask
to disconnect, then connect.

Last, open a terminal window and type ipconfig <enter>. You should see
a table of information on your NIC. One line should be your IP
address. It should be something like 192.168.0.1. If it is very
different, it means you not getting an IP address from the router. Try
resetting the router to factory defaults.

Good luck, jimbo