RE: Video problems after Windows 10 upgrade and subsequent rollback to Windows 7
The service manual should help assist in helping you replace the cable. If you find it complicated, I would suggest you to get it replaced by a local tech, perhaps?
There is no physical switch as such for the LCD close. Since you had previously mentioned that the display is faint and some image can be seen when an external light is focused on it, it is an issue with the inverter -read more here - http://bit.ly/215SXUO - However, in most displays, the inverter is part of the LCD assembly. And hence, you had previously replaced the LCD.
You could try reseating the LCD cable and check before you go ahead and replace the same.