Hi everybody. My iMac is not starting up. I have a technician guide for a previous model (mid 2010), and following the...

Answer on iFixit Jay writes: "Is the AMD chip the real problem anyway? Could I have a different problem?" I think you got it right here. I got the MacBook Pro on which I am now writing from a friend. He got it from the university where he works, and some time ago the machine started having glitches like you describe, but with only its own display in use, and also with very light graphics load, so it could not be the discrete GPU. Furthermore, my friend noticed that the problem occurred mainly while moving the machine or when awakening it from the sleep state. After some inquiry I found Screen + 3 beeps problem!. (the editor doesn’t get the permalink to the answer of santiagodelatorre, but that is what I’m pointing at). It seemed very logical to me that the problem was the RAM slots. But for the university the only solution was to change the motherboard; (un)luckily the MacBook was too old and not worth that expense, so my friend, under my warm suggestion, just kept it. And, if I would have managed to...