Wi-fi weirdness; laptop wanted

I don't understand this.

I have an older laptop, so I use a PC Card for a wi-fi connection. It's a Netgear WG511T, which is compatible with 802.11b and 802.11g. It works just fine with a b or a g connection, as long as WEP is enabled. It doesn't work anymore (at least not consistently) with a g connection that doesn't have WEP enabled (e.g., a coffeehouse with free wi-fi). It used to work under all conditions. By "doesn't work," I mean it gets stuck trying to acquire an IP address, or it gets an IP address but then can't ping the router, or it can't resolve any domain names.

I have an old CompUSA WLAN 802.11b adapter (actually made by Gigafast). It works fine with the non-WEP 802.11g connection at the coffeehouse.

it could be something the matter with the Windows XP installation. (It didn't work under XP SP1, and when I upgraded, it still didn't work, but I got more informative error messages.) I have reset the stack using netsh and reinstalled the TCP/IP protocol on each adapter, but nothing seems to fix the problem.

It's possible that the Netgear adapter is going bad; I don't have another 802.11g adapter to test. The fact that it always works if WEP is enabled on the router makes me think it must be software.

What would really help is a new laptop, or at least a newer, gently-used laptop. I've had good luck with buying used from individuals. My first two laptops were bought from co-workers. Each was about a year old at the time and cost about half what it would cost new. The 1997 Toshiba Satellite 435, which runs Windows 95, is still running, although it can't do much. The 2002 Dell Inspiron 4000 is still going, too, although every component except the LCD has been replaced at least once.

If you happen to have a gently used but fairly recent laptop that you'd be willing to sell cheap, drop me an e-mail at the address on the left. What I'm looking for would have Windows XP (NOT Vista!) and media for drivers, built-in wi-fi, USB 2.0, a DVD writer, at least 1 GB RAM and at least 60 GB disk. I have a preference for Dell -- they're easy to work on, and Dell provides step-by-step instructions for taking them apart and putting them back together again.