Reboot after shutdown (Ubuntu 14.04 (also 12.04); Dell latitude E7440)

I experienced exactly the same problem on my new computer Intel i5-4440 processor and Intel DB85FL motherboard (4th Gen). First I faced this problem with Ubuntu 13.10. and subsequently after upgrading to 14.04 LTS.

I did the following recently to solve this problem of SHUTDOWN and automatic REBOOT again withing a second or two.

I have Intel Visual BIOS. On power up I pressed F2 > POWER > Wake On LAN from S4/S5.

This has 3 options. 1. Stay Off, 2. Power on - Normal Boot, and 3. Power on - PXE Boot. My computer was set to #2, which was making it automatically REBOOT after SHUTDOWN. I now changed to #1 option mentioned above. Now it is okay.

Hope this would work for you as well. Best wishes.

I also faced the same case on my Acer Aspire E1-470G using Ubuntu 14.04. These steps worked for me.

1. Type in terminal

   sudo nano /etc/default/grub
   

   then find a line

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
   

   Modify it to

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" acpi=force apm=power_off
   

2. Type in terminal sudo nano /etc/grub/modules then add apm power_off=1 under line lp. Save and close the terminal.

3. Update the GRUB

   sudo update-grub