Hi. My name is***** you for your question and the opportunity to assist.
What is meant by the boot menu being locked?
Can you tell me the exact wording that appears on your screen?
When you start the laptop normally, are you able to log in to Windows or are you
having some other type of issue that you can't get in to the machine?
Start the laptop and as soon as you see the Toshiba screen begin steadily tapping the F12 key.
This needs to be done quickly as the Toshiba screen doesn't stay up very long.
Try this: hold down the power button until the laptop shuts off. (about 4 to 5 seconds)
With the laptop off hold down, and keep holding the F12 while you power on the laptop.