Hi, I am A. Stevens here to help with your question!
So at this time, you've already replaced the LCD screen once correct?
There are a few other components that could be causing this issue
One could be the cable connecting the board and the LCD is defective
I agree but these do not fail very often and they are difficult to get for this model.
I assume you've tried resetting the connection already?
Yes I have
Do you know how old the Toshiba is?
It has windows 8 installed so about 2 years
I'm afraid if you already replaced the screen, and tried resetting the connection, you may have some other faulty hardware (IE on the motherboard) that may not be worth replacing.
The reason I ask is that sometimes the manufacturer (Toshiba) might replace it even if it is out of warranty.
That might be your best bet at this point.
But I took a look at the price of the unit, and it proabably wouldn't be worth trying to repair with out of pocket cost.