All Toshiba keybaords have Function keys. it will be the 3rd from the left, top row. To get to boot menu you need to press F12 key. If you can not get to the boot menu, you most likely have fast boot enabled.
No reason to downvote the post. I worked for Toshiba as tech support for over 3 years and know thing or two. I would have attached a photo of the keyboard of your model but cannot see the way for it on this thread.
I would suggest to remove the battery and unpluge from the mains. Insert the battery and mains back, hold down the F2 key and turn the unit on, this way it should go to BIOS.
Have done tech support myself for years, not disputing they have fkey functions but the keys are not marked as such and the keys which normally marked as such do not work.
The downvote was for 2 reasons -
First in your initial response it failed to recognize exactly what was described evident by response -
"THe issu can be cauesd by curruptd HDD or changes in BIOS" - when post clearly stated HD's were stolen and replaced with new HD's
Second there are no marked fkeys which was stated(included model to view online via google images or whatever to familiarize with to see the actual keyboard layout)
Being a efficient tech requires recognizing the issue exactly for what it is quickly(how personally advanced to upper tier of tech support quickly)
In any case appreciate the attempt to help(the downgrade was not for a failure to resolve)
Will try your suggest about removing battery, but yet again with no designated fkeys on keyboard and using those in location normally as such which have not worked already provides little hope. The fast boot option is obviously enabled, will probably remove new HD's and load windows on a different PC then reinstall HD's to this laptop, windows 8 was the original OS, concerned this will cause an issue since it had been upgraded to windows 10.