OK, this has happened to three of these laptops so I will temporsrily rule out a
>hardware failure
>
>It says "Windows cannot find any networks". The problem is intermittent and can happen
>again in five minutes or five days.
>
>As this is happening I am remembering something from the past. We bought a cordless
>camera and set it up and the cordless phones in the house would no longer work, unless
>you were within inches of the base. This leads me to believe it is some sort of
>interference. We are taliking three laptops here, and the problem is getting worse. And
>thsat is cannot find ANY networks means the wifi in the house is probably not going bad,
>or it would have found the other ones in the neighborhood.
>
>I do not have a spectrum analyzer, but I do have an old YV woith a UHf band if that would help.
See if you can find a WiFi scanning-and-analysis application which works with your variety of Windows and your particular WiFi card. They're sometimes called "site analysis" programs.
Depending on the WiFi adapter, it may be able to read out the noise level on each of the (overlapping) WiFi channels, as well as any actual signals it finds.
Microwave ovens emit RF in the same ISM band that WiFi B/G use (2.4 GHz). So do many other devices, including many cordless phones.