I have installed LXDE from Ubuntu software center,(didn't install the addons i.e. chromium, GUI login manager, lxtask).
Now while logging in I have options allowing me to choose between LXDE and unity 3d and 2d ,gnome. So how do I remove all those other desktop environments and keep LXDE just like in lubuntu, but i want to keep my installed programs. I'm using 12.04LTS.