首先，不能正常关机：
Q: Ubuntu点击关机后停留在splash界面不动
A: 解决方法来自Shutdown does not power off computer
I have the same problem and found a solution which worked out for me.
Type in terminal:
- sudo -i (to get a root shell, sudo gedit is not recommended)
- gedit /etc/default/grub
- Find the line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
- Change this to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=force"
- Save the file and close the file.
- Finally, in terminal: update-grub
- exit (to end the root shell)
I found it here: Dell Studio 1569 Cannot Shutdown in Ubuntu 11.10 or 12.04
其次，不能正常开机：
Q: 开机后，屏幕提示 “PXE-E61: Media Test Failure, Check Cable” ，然后就是跳转到找不到操作系统。只能通过手动选择Ubuntu这个启动项才能启动操作系统
A: Waiting...
可参考：http://www.tech-faq.com/how-to-solve-pxe-e61-media-test-failure-check-cable-error.html