knoppix 3.7 hangs at reboot

Hi,

I'm running Knoppix 3.7 on an Asus P4S800 motherboard and I am having problems with the reboot/shutdown.

When I reboot or shutdown, the CD is ejected after pressing enter, the message "Shutdown Completed." is shown, and the cursor stops blinking.
The machine does not turn off and does not reboot.

I can't make a dmesg log of the machine at the moment.
It's an Intel Pentium 4 2.4GHz (no hyperthreading) on an Asus P4S800, chipset SiS648FX.

Enabling or disabling ACPI has no effect.
There are no BIOS updates available, we are already using the latest BIOS.

What could be the problem and how could it be solved?

Try some different cheats like noapic noapm nolapic apm=power-off and so on. Have a look at Cheatcodes under the Documentation tab at the top.