Intel 4965AGN WLAN problems with Airport Extreme router

[Edward Mendelson]

After many weeks of experimenting and searching, I'm posting here in the hope that someone knows a solution.

My family uses a variety of Thinkpads (T61 and X61 models) that have the Intel 4965AGN mini-pci wireless adapter. We also have an Apple Airport Extreme 802.11n router, because that's the only router I've tried that has enough range to go through the walls in our ancient apartment house. We have the router set up (correctly) for 802.11n only, with WPA2-Personal and AES encryption. With the Intel wireless card we have these results:

Ubuntu Linux 9.10: Connects perfectly.

Windows 7: Connects perfectly, but only after applying the technique described here:

http://blog.natesilva.com/post/25055361 ... o-an-apple

Vista: Tries to connect but can't get an IP address from the router.

Windows XP: Tries to connect but can't get an IP address from the router.

All OSes are up to date; I'm using the latest Lenovo drivers.

There seem to be two solutions to the problems under Vista and XP:

(1) scale back security to WPA (not WPA2) and TKIP encryption (not AES); I want to avoid this, because TKIP has been cracked, and because TKIP seems to produce a lower connection speed than AES;

(2) replace the Intel card with an IBM/Atheros card; I want to avoid this because it's an expensive solution, although I tried it in one machine, and it solved the XP/Vista problems instantly.

Does anyone know of any solution for the problems described above in XP and Vista that doesn't involve replacing the card?

I've already tried using Access Connections instead of Windows configuration and I've tried using Intel's drivers instead of Lenovo's. Neither solution works. I've also tried specifying an IP address on the client (doesn't work), setting a specific wireless channel (of course that didn't work, but someone suggested it when this issue was raised on another forum).

If anyone in this expert forum has a solution, I'll be very grateful.