Windows 10: Win 8.1 Toshiba Satellite Laptop-Black horizontal Line 1/3 across top-L of screen

I have a Toshiba Satellite laptop with Win 8.1 and Office 2016. Yesterday a thin black horizontal line appeared in the upper L top of the screen. I tried to capture an image of it but it is too close to the top of the screen.I have replaced the guts of another Toshiba which is no longer around. I am not sure of this is a hardware or software driver? issue or how to solve it. I have rebooted, I have run the drivers troubleshooter and it could not find a driver.Any advise will be welcome. Thank you and I hope you and yours are safe and well.

:)

 

horizontal black line on screen

Without you having posted a screenshot of it, it may point to either corrupted graphics drivers or a possible failing hardware part.

We don't know if the horizontal black line is at the top, bottom, middle or where on the screen or the thickness of it or anything else about it.

 

horizontal black line on screen

Without you having posted a screenshot of it, it may point to either corrupted graphics drivers or a possible failing hardware part.

We don't know if the horizontal black line is at the top, bottom, middle or where on the screen or the thickness of it or anything else about it.

Hi

the line is fine, straight, black, horizontal, black and about 6cm long. It is situated 3cm from the bottom of the screen, and just to the right of centre. I have tried to take a screen shot of it but when I paste to Word it does not appear on the image.

 

toshiba satellite p850-00e bootable usb windows 10 black screen

Question: Any suggestions how I can get my boot from my usb key on my toshiba?

PC:toshiba satellite p850-00e
USB:San disk 128 gb
Brand new solid state: King Dian 128 GB solid state

Description:
Attempting to install windows 10 on a Toshiba satellite p850-00e with a new solid state drive I just put in.

I press F12 loading, i get the boot menu. I select usb and I just get a black screen. No prompt to windows 10.

I tried the same usb on my desktop to boot from and it worked

1. boot menu option to be CSM.
   
2. boot priority to be top priority. Made no difference.
   
3. Boot speed is normal.
   
4. Boot security is disabled