ubuntu狀態欄消失的解決辦法

剛從8.04升級為12.04，可能因為系統沒有很穩定，不知道按到什麼按鍵，屏幕上方的狀態欄不見了。
到網上查找解決方法，找到一篇文章，說可以使用如下的語句解決：
sudo apt-get autoremove
sudo apt-get install gnome-panel
可是我在執行完後，重啓系統，在登陸我的帳號時提示如下的錯誤信息：
failed to load session “Ubuntu”
這下連桌面都沒有辦法進入了。
找到如下網頁：http://riveridea.wordpress.com/2012/03/22/how-to-solve-failed-to-load-session-ubuntu/
Please open tty (virtual console, text mode only): ctrl+alt+f1
Enter:


sudo apt-get update


sudo apt-get install ubuntu-desktop


sudo apt-get -f install


sudo dpkg-reconfigure ubuntu-desktop


sudo reboot
If above wasn’t sufficient try:


sudo apt-get install gnome-session


sudo apt-get install lightdm


sudo apt-get install unity-greeter


sudo dpkg-reconfigure lightdm
## The install commands will tell self-explanatory if it’s already installed or not.
Just in case, the same can be done via recovery mode.
Press [Shift]-key right after boot to view boot menu, select recovery mode and select root shell (no need for ‘sudo’ there).
You could also view log file in either one of them in order to verify if essentials have been removed and install it again.


sudo nano /var/log/apt/history.log
這樣執行完前面重新安裝了desktop之後問題就解決了。