Hello
Why updating the BIOS if your computer is not able to start properly?
Either the internal display is malfunctioning and doesn’t show a picture or it’s serious hardware malfunction like mainboard itself.
At first I would connect an external monitor before you start the notebook to check if it’s a monitor problem or not. After you have connected it, turn on the computer and press FN+F5 key combination to switch on external monitor.
If it doesn’t help check this article:
http://forums.computers.toshiba-europe.com/forums/ann.jspa?annID=21