First boot into the BIOS and look for weird settings.
Specially "Plug'n'Play OS installed", this should be off on modern distros, but it can have changed (again)...
Try disabling the ACPI passing acpi=off as an arg to the kernel.
Once you get it running try to install the Toshiba-specific modules (can't stat which). Here is more info:
http://www.buzzard.org.uk/toshiba
If the are not compiled you will need to recompile the kernel and activate:
Processor type and features >> Toshiba Laptop Support
and
Power management options (ACPI, APM) >> ACPI (Advanced Configuration and Power Interface) Support >> Toshiba Laptop Extras
I would suggest recompiling and setting
Power management options (ACPI, APM) >> CPU Frequency scaling >> Intel Speedstep to be compiled into the kernel.
This has the advantage that frequency scaling and power management are started at system power-up. Perhaps KDE complains about a missing module, but Speedstep and the kernel are smart enough to manage the system by themselves.