Thanks mayer !!
Since you have good video on the external monitor your GPU (graphic card) seems to be OK. Most of the time vertical bars means bad LCD panel (faulty LCD electronic board). You don't have any video onscreen but two faint vertical bars and a single pixels row ? Am I right ? You could check your LVDS (video) cable connection to the logic board. Take off the connector from the socket and fully reinsert it. Another test is to apply pressure with your fingers each side of the iSight camera and on both sides of the screen and check if there's a change onscreen. Any change in the screen when playing up and down with the lid ? When closing the display does the MBP goes to sleep normally ?