Some Toshiba (and others) laptops cannot be 'updated' to Windows 8....it is not supported. Did you check with Tosiba before you tried this? Do they have a bios update for your model? Do you have Intel and AMD graphics? If so you can try the Leshcat drivers. You will not be able to install any driver from AMD...Toshiba has customized the graphics to work with their system, and cannot use the 'generic' drivers that AMD offers.
Edit: On the Toshiba page you referenced, there is a link to "Cant find drivers for Win8"...which takes you here. It tells you if your laptop will support Win8 or not.
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08:59 PM by