I had the pink vertical lines suddenly appear on my early 2011 MacBook Pro 15" a couple days after I replaced the touch pad. By accident, I also found that the screen went completely white if I opened the lid all the way - maybe 180 degrees but the screen images (still with the pink lines) restored immediately when I returned the lid to 90-120 degrees. So the big clue, of course, is that I had disassembled the innards almost completely, it was my first time to do so, and I already had to reopen the case once before to properly reconnect the keyboard ribbon cable. So, thinking it was some connection near the hinge, I reopened the case and looked for a loose connection near the hinge, and voila! the display data cable (top right corner with fans at top, see photo) was loose! I just used my fingernails to push the little "ears" to put the cable connector all the way in. It worked! Yay!