If the laptop won't let you get to the BIOS, try unplugging it and removing the battery for about 15 seconds. Sometimes the computer gets stuck doing soft reboots (restart) instead of a hard reboot (full shutdown and power up), which may not give you enough time to enter the BIOS. Completely cutting off its power will force it to hard reboot next time.
If you know the key to bring up the boot device menu, try that, and see what happens when you specifically tell the computer to boot off your boot drive.
For a long time, Toshiba had a love affair with Intel's RAID drivers, and even configured their single-drive laptops as RAID. So try going into the BIOS and setting the SATA interface as RAID. See if that makes it bootable.
Have you removed or replaced any of the drives recently? Starting with Vista, Windows doesn't need the OS to be on the boot drive. So it's possible to misconfigure the computer to boot off of one drive, then switch over to the other drive to start Windows. When that happens, people often remove/replace the non-Windows drive, and suddenly the computer can't boot anymore. This is relatively easy to fix with the bootrec command, just make sure you're running it on the proper drive.
https/neosmart.net/wiki/bootrec