You're almost certainly right, I've not had success with it myself, and I originally thought the same, but I've heard anecdotal evidence from others that it's w

You're almost certainly right, I've not had success with it myself, and I originally thought the same, but I've heard anecdotal evidence from others that it's worked for them, and there are a few mentions of it online, including a video at http://www.anandtech.com/show/6840/hardware-tricks-can-you-fix-a-failing-mobile-gpu-with-a-hair-dryer http://www.anandtech.com/show/6840/hardware-tricks-can-you-f... , but I've also found mentions that the likely cause of the hair dryer trick is old capacitors being temporarily "revived" by the heat (http://www.instructables.com/id/Fix-a-dead-power-supply-using-a-Hair-Dryer-Reflow/ http://www.instructables.com/id/Fix-a-dead-power-supply-usin...). It seems like something is being at least temporarily repaired by the heat, but it's probably not anything to do with solder.