看不到上下的菜单栏，但是有桌面。要么是配置文件，要么是gnome缺组件
先执行
sudo apt-get install --no-install-recommends ubuntu-desktop gnome-panel gnome-settings-daemon metacity nautilus gnome-terminal
安装必要的组件，然后把xstartup修改为如下：
# Uncomment the following two lines for normal desktop:
# unset SESSION_MANAGER
# exec /etc/X11/xinit/xinitrc
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
x-terminal-emulator -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
x-window-manager &
gnome-panel &
gnome-settings-daemon &
metacity &
nautilus &