Thanks for the info Patrick. Hoping that his router is ok too. Any additional thoughts on that?
He has a new router coming, can't hurt to try it and see if the Dir-825 is the culprit. Being almost certain the laptops depending on how old they are have an unknown version of draft "N" in them. Letting the OS power down the WiFi adapter is a setting I always turn off in my windows setting for the WiFi adapter, that causes some problems like you are seeing sometimes too.
The Netgear router that you mentioned I just pulled out of a family members house and replaced it with a D-Link, it would NOT work with their Kindle, it worked with Ipods, Androids, Laptops, you name it, just not the Kindle. Since I put the D-link in, no problems. This was just a couple of weeks back, still to this day, I have no clue why the Netgear would not work with the Kindle.
Some times there are hardware differences that even an engineer can't explain, that is why I bought the little dongles, one works, they all work. I bought like 8 of them(only needed 5), I was affraid they would come out with a new rev and screw everything up with my "if one works they all work" theroy.
I wanted to use channel 13 on my network at home, so I went out and looked for EU software for the Dir-825, I do believe that 2.05EU is the version that went from draft "N" to the new 802.11N, dont remember where I found it, but it was legit and changed some other things for EU compliance too that I was not happy about, so I did not do the switch and stuck with US 2.06.