"Limited or No Connectivity"

wireless issue:
First off, I'm runnin' XP w/service pack 2 installed on my laptop, and a Linksys router.

The problem:cry :
Frequently, I have 4-5 bar/"excellent" signal strength however my computer insists that I have "Limited or No Connectivity". This happens randomly 1-2 times a week but seems to have gotten worse over the last couple days.

Bits of info that may or may not be relevant:
--The "Repair" function does not fix it-- "Repair failed- Unable to connect to the wireless network"
--Reseting the router works sometimes, but not others.
--Moving the computer/router doesn't seem to help either.
--When this connectivity issue is happening, sometimes the connection says it's security enabled (it is not security enabled)-- if I "Refresh Network List" sometimes it still insists that it's security enabled while other times it shows up as a normal open network (still with excellent signal strength and limited or no connectivity) If it decides that the connection is security enabled, it prompts me for a password-- which doesn't exist! System restart sometimes helps; usually not.
--I also seem to have a fluctuating ability to detect neighboring wireless networks. Sometimes I pick up 10 area networks, hit the "refresh network list" button and then find only one or two. It seems like that should be fairly consistent if everthing is in good working order. (this may have nothing to do with the issue at hand but I'm trying to give as much info as possible)
--The speed fluctuates from 1-11mbps and seems to have little correlation with the signal strength. (I don't understand this?-- but I'd like to if someone could send me to a tutorial!)
--Seems to be a random problem-- time of day nor anything I am working on seem to consistently impact the situation.
--The problem seems to have gotten worse over the last few days. Previously, it would happen once or twice/week and then would clear up (sometimes) if I did a system restart.
--When everything is working, it works as expected-- speed stays around 11Mbps, signal strength is 'very good' to 'excellent' and there's no oddball drops in service. Until it goes bad and I get the "limited or No Connectivity" message from outa-da-blue which happens sometimes from startup and sometimes in the middle of working online.
--Sometimes (like now), when I cannot get my Linksys connection to function, I can try to hobble onto a neighbor's wi-fi (she's a friend and Oks it) and seem to have slightly better luck. tho it takes forever to get hooked up. When, and IF, I finally get connected, it's super-sloooooow even tho the signal strength is "good" to "excellent".
--When I can connect to my system normally, I can connect to hers equally well.
--I tried typing http://64.233.183.103 into the address bar and it went to google-- according to another post here, that means my DNS settings are wrong. Is this true? How do I fix it?
--Found this here and tried it too--> [Try resetting TCP/IP. Click start > run and type 'netsh int ip reset c:\resetlog.txt' (without quotes). Try again.]-- that didn't seem to change anything either.



Maybe helpful:
--I downloaded a program called "Network Stumbler" that is supposed to help define wireless problems but can't seem to figure out what it's telling me about my connection. (I'm a bit of a nube)

other Qs:
--Is there a simple program that can help me view signal strength, speed and keep track of whatever it is that's befuddlin' my connectivity?
--How do you word-search the archives here? {nevermind! the search button appeared after I signed in}


Thanks for taking the time to read all this! Love the forum here. Take care :wave