I'd like to install NERDTree (I'm on 32-bit Win 7, anyway).
And to make vim plugins management easier, pathogen needs to be installed first. So here's the steps:
Take pathogen.vim and put it on C:\vim\vim73\autoload
Make the 'bundle' directory (C:\vim\vimfiles\bundle)
Do 'git clone https://github.com/scrooloose/nerdtree.git' in the bundle directory
Put this line in your .vimrc: execute pathogen#infect()
Of course, every time you run gvim, NERDTree will also run, because it's invoked by pathogen and pathogen is autoloaded. Sometimes I find this to be annoying. So is there any way to make NERDTree to be able to run manually? But I do not want to remove pathogen because with it plugin removal is so easy: just get ride the plugin directory from 'bundle'.