Trying to install it (in safe mode) but I get the "Failed to load detection driver" error
A very strong indication that your graphics is failing. It is not being able to take any driver. But, your AMD Radeon HD 7670M should take all those drivers properly. Have a look .... go to
Download Drivers ... put these values there ....
and display results. It results ....
Mobile
So 14.4 WHQL also should be applicable for your card.
As laptop graphics are complicated, take it to Toshiba. Ask them to fix it. It may be needed to replace the graphics chip.