The modem/router (Westell Versalink 327W) was part of the deal with
Verizon's DSL promotion. When I called Verizon's tech support and
explained this problem the first time, I had the same WEP security
setup except Shared Key instead of Open System. The tech told me that
they instruct people to set up their wireless network with Open System
WEP, and if you want to use any other features of the router (e.g. WPA
security or Shared Key WEP, etc) then you are on your own. They don't
extend their support for anything more complicated. At that time I
changed from Shared Key WEP to an Open System WEP (128 bit), and waited
for a couple of days. Then the problem happened again.

This problem has not happened in the last day, but it is hard to
reproduce because it takes a whole day of inactivity to invoke , and it
occurs half the time.

I don't know what the difference is between WPA and WEP. Have you ever
heard of the router "forgetting" its WEP setup? If that is a problem
inherent in WEP, then I could try WPA.

Also, is it possible that the wireless card built into my laptop may
have any limitations? I had been using a WEP setup with my cable modem
+ netgear router for about a year. Everytime the netgear was
broadcasting, my laptop would pick up the signal and connect. This
problem is different: laptop sees the router broadcasting (SSID is
visible in "list of available wireless networks") and does not connect.
Automatically or explicitly.

Thanks