Intermittent wi-fi connectivity issue on Win 7 PCs only

I have 6 wireless devices at home: Toshiba laptop with Windows 7 Home Premium x64
pre-installed, Dell Inspiron ONE 2320 with Windows 7 Home Premium x64 pre-
installed, an iPod Touch gen 3, Acer laptop with Ubuntu Linux 11.10, my wife's
Android Blackberry 8230, and a Sony Blu-Ray DVD player. All of these devices--
except my 2 Windows 7 boxes--connect to my wi-fi flawlessly, and they stay
connected without error.

The two Windows computers go through this cycling process of connecting and
disconnecting every few minutes (many times per day). Sometimes just clicking on
my wireless connection in the lower right-hand corner of the screen with the
little yellow triangle with an ! in the middle, clicking disconnect, then clicking
re-connect fixes it. Sometimes I just have to walk away and do something else for
either a short while or a long while, and it will have resolved the problem
itself.

When the 2 Windows PCs have disconnected and are taking a "longer" time to
reconnect (10 minutes), I can at that moment walk over to my Ubuntu laptop or pull up my iPod and get online and stream video or whatever. Or I can stream Netflix to my DVD player or I can browse the web on my wife's Blackberry--and I get the little
arrows that show it's using the wi-fi and not the cellular connection.

I have gone into the properties of the network adapters and have deselected the
checkbox that says "Allow the computer to turn off this device to save power." I
use the High Performance power option, anyway, but I still have made sure that box
is not checked.

I have downloaded a utility called inSSIDer to see which wi-fi channels my
neighbors are using. They are all using channels 2 or 6. I am using channel 11, so
there's no overlapping of signals.

In my house I have two 900 MHz phones--which shouldn't be a problem--one of which
is 12 inches away from the Dell I'm having trouble with. I can unplug them and
remove the batteries from the phones and the wi-fi problems still persist. I also
have a microwave about 15 feet away from the Dell, but I never use it. I have not
unplugged it, but I don't believe it's a problem, even though it can use the 2.4
GHz signal.

I can shutdown or unplug all other wi-fi devices in the house and the Windows
computers will still have the problem.

I have two wireless routers in my possession--which are NOT plugged in at the same
time--that I have used for troubleshooting. One is a Netgear N600 and the other is
a Cisco EA4500. The problem persists no matter which router I plug in. I have set
them to factory defaults and I have tinkered with them to an extreme, carefully
trying one setting after another. Still, the intermittent connectivity problems
with JUST the two Windows boxes persist.

I run Microsoft Security Essentials and SuperAntiSpyware on both computers. There
are no viruses, there is no spyware.

My LMHOSTS file is clean and I have flushed my DNS. Still, I have problems.

I am using WPA-2Personal security, using AES encryption on both computers. I have
tried WEP, but I don't want to use it as it's insecure. WEP did not help. I have
not tried using no security, as I don't think this is a viable option. Having an
unsecured network is unacceptable.

I have tried using DHCP and I have tried using static IP addresses. Neither option
seems to matter and the problem happens either way.

Here is a print-screen of my IPCONFIG:


What is going on? What have I missed?

Congratulations, you one of the few posters here who has already self diagnosed most every problem I can think of. The ipconfig looks fine. Usually when I see this type of problem it's from channel overlap but it looks like you have that covered.

That said I have no idea what the problem might be. The only thing I can suggest is to make sure you are using the latest drivers for your Windows 7 machines. The manufacture's web site is the best place to look for those.

It may be worth while to update the firmware on the router, which ever one is being used I'm not sure.

Updating the NIC drivers is a good idea, and I have not done that. Thanks.

The problems just started a few days ago. Until then, we haven't had any connectivity issues, and my other devices work w/o error.

I just installed inSSIDer on my wife's Toshiba laptop and walked around the house with it. I see many more networks with her laptop than I do on my Dell all-in-one PC here in the kitchen. There are 2 other people using channel 11 and 1 other using channel 10. Their signals are weak (-89 to -94), and my signal is excellent (-40). Maybe this is the problem. Maybe their router is set to auto and it has recently chosen channel 11?

Why do my other devices connect fine, though? Did something change in a Windows Update I'm not aware of? Just thinking out loud.

A print-screen from my wife's laptop as I walked near my router shows even more wi-fi connections. Maybe I should try channel 1? (I am obviously the green connection.)

Former MCSE said:

A print-screen from my wife's laptop as I walked near my router shows even more wi-fi connections. Maybe I should try channel 1? (I am obviously the green connection.

Yes I believe this is a channel overlap problem from what I'm seeing there. For some reason Windows 7 seems to be particular about channel overlap and disconnects are common in crowded area's. I'm surprised it's a problem for you considering the signal strength looks to be rather weak on the other channels.

In your case I would go with a channel in the lower ranges starting with channel 1 but you may need to experiment with different channels to find the best one.

That is one crowded bunch of wireless channels for sure.

If that doesn't work you could try the 5Ghz band, your Cisco router appears to be dual band but of course your wireless adaptors need to have the 5Ghz capability as well. :)