Installed Mint LXDE on Dell Inspiron 4100 with 256 MB ram yesterday. I installed Windoes XP wireless drivers for my D-Link AirPlus DWL-650+ wireless cardbus adapter. I could see all available wireless networks, but could connect only with unencrypted networks with the XP drivers. Tried the Windows ME drivers, and wireless is working great now.
Just wanted to post this in the hope that it might help someone with a similar problem.
Great distro!! Just what this old equipment needed!!