Laptops are about 50x harder to work on than desktops so you might just want to think about replacing it or taking it to a computer store.
The latter will probably charge more than it is worth to try and fix it too.
Even if it was a desktop computer, the next step would probably be to start trying to replace things, probably starting with the motherboard and that is not going to be cheap and definitely not easy to try to do with a laptop.
I had read about a key combination to start boot from USB pendrive when this occurs.
Maybe Fn+B or so.. before to press start button and standing pressed while it begins to start...
Do you asked Toshiba SAT?
and what about use PRD, Phoenix Recovery Disk. It is the same but using a boot BIOS from CD ( maybe we could use an USB pendrive too).