Hey Guys,

my problem is the following: When trying to shut down the system, it reboots instead. There is a short moment when the computer has no power between shutdown and reboot.

Dell Inspiron 5150
Ubuntu 64-Bit 12.04 (I just installed Ubuntu on the system; there has never been a normal shutdown with it so far)
Bios A02 (latest version)

Measures so far:
shutdown now, init 0 have the same effects.
I updated the BIOS only to realise that A02 is already the latest version. It changed nothing. I changed my default Grub entry in /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="acpi=noirq quiet splash", nothing.
I also searched Google for "ubuntu 12.04 restart instead of shutdown" but none of the posts could help me so far, please note that most of them redirected to this forum.

If you need any further information, feel free to ask.

Thank in advance,