lxdm won't login to Ubuntu 2d or Gnome classic

view story

http://askubuntu.com – I installed Ubuntu 11.10 on an old Dell Centrino/512mb machine that was running too slow with Windows to be useful. I am completely new to Linux and muddling my way through as well as I can. The machine still runs pretty slow on Ubuntu. So I loaded the Gnome shell and the classic (no effects) runs fairly well. Everything seemed to be fine up until this. But still not as fast as I'd like. I read that Lubuntu is even lighter, so I installed Lubuntu-desktop. It still defaulted to the "Ubuntu login" or as I came to discover it's called, lightdm. I changed this to lxdm. Once I did that I suddenly (HowTos)