First, check the setting in "desktop sharing" so that other user can control this desktop.

Then install the xrdp to transfer the linux VNC protocol to windows RDP protocol.
sudo apt-get install xrdp Now you can connect this desktop from windows by using "Remote Desktop Connection ".
The default port is ":3389", or your can edit it in "/etc/xrdp/xrdp.ini"


trouble shooting

If the remote screen only show wallpaper with nothing,
set the following content to ~/.xsession
gnome-session --session=ubuntu-2d or
gnome-session --session=gnome-classic
and restart xrdp.
sudo service xrdp restart or
sudo /etc/init.d/xrdp restart
If it still show wallpaper with nothing, install the following package.
sudo apt-get install gnome-session-fallback
and restart xrdp.
sudo service xrdp restart or
sudo /etc/init.d/xrdp restart
If there is only black screen with nothing, disable the "Allow me to save credentials" in windows "Remote Desktop Connection".


Reference: 使用 XRDP 從 win7 遠端 Ubuntu 12.04LTS 桌面