T61 a/b/g wireless -- EXTREMELY slow authentication

[LoneWolf]

Hi all,

I'm the recent owner of a T61, specs as follows:

T8300 CPU, 4GB RAM, 120GB (5.4k) HDD, DVD writer
15.4" WXGA display, Quadro NVS 140M
Bluetooth, a/b/g Wifi (Atheros chipset), Fingerprint reader

I was running Vista Business, but downgraded to XP Pro using the Lenovo downgrade discs. The machine is joined to my domain at work (I'm a sysadmin there) but I often use it at home.

My problem is this: Authenticating to a network share (i.e., Start->Run->\\(ip-address)\sharename) at home over wireless is glacially slow. It can take 90 seconds for the login\password screen to show up. Once in, it's fine for reading files, but if I save something to the system (best example, doing Right-Click->Save As... in Firefox and saving to the network share) also takes an incredibly long time.

The machine I'm authenticating to is no slouch (Core 2 E6600, 4GB RAM, wired in via gig Ethernet to my router), and I'm using a D-Link DGL-4300 GamersLounge router configured for WPA-PSK security, which has been great for me for two years. Both my previous Powerbook G4 Titanium and Dell Latitude C640 got an authentication prompt within 2-3 seconds. I disabled SuperG on the router to see if this might help as well; no dice. This is extremely frustrating, made more so by the fact that regular surfing over WiFi is perfectly fine. Connecting to the system with Remote Desktop is also speedy, so this authentication issue continues to make no sense to me.

Does anyone know if there is a driver issue, or some sort of problem that could be caused by existing ThinkVantage software? I've uninstalled some of the apps I haven't needed, but have kept others. If anyone has any ideas, I'd be grateful.