ubun2

I have a Toshiba laptop A300-157 and Ubuntu 9.10. At the shutdown of the computer system is restarted. Only when the power cord off system shut down normally. I tried Ubuntu 10.04 and the same is happening.
uname-r2.6.31-22-generic-pae
BIOS version is V 1.9
I tried:
1. remove the "splash screen" in grub,2. sudo shutdown-h3. sudo halt4. sudo shutdown-h-P5. acpi_osi = Linux6. adding acpi = force in rough7. after adding "reboot = no Shutdown = no" ---  system restarts again
with: sudo gedit / etc / default / haltand fail to mention adding a line that looks like this:# Default behavior of shutdown-h halt. Set to "halt" or "PowerOff./ Sbin / rmmod snd_hda_intelHALT = PowerOff
with: Alt + SysRq + the system is restarted again.
Does anyone any suggestions to solve this problem?Thanks